Just keep trying.
PhD applications are a lottery.
I once applied for a PhD in science at a UK university. The application was unsuccessful.
I then asked for feedback. Their feedback was along the lines of me being a very cute kid (!!) - and that is about all they said - even though there hadn't even been an interview, and the staff hadn't met me either in person or online. I am still keeping that email as evidence.
I am aware that many people give advice along the lines of getting more experience in either research or industry, publications etc so that you have more chances of being accepted to the PhD. My experience was very different.
Other experiences you may have is that you apply for a highly competitive PhD - one that asks all applicants to have a first and possibly other requirements - and then you discover your supervisor is an incompetent who doesn't know the science they should know in their position.
It shouldn't be this way but that is how it is.

abababa,
I couldn't agree more with "volume of work, which is often over-appreciated compared to volume of thought". Yes, there is a very bad tendency nowadays (dangerous to science / research / art/ culture etc) of not appreciating thinking and, instead, appreciating "hard work".

The Japanese - a people with a high work ethic - have a saying "not hard work but smart work".

Spending lots of time to think deeply helps the progress of research much more than "working a lot" - if, of course, the PhD student / researcher is doing it honestly and doesn't try to cheat by saying that "they are spending their time thinking" while they are actually doing nothing.

The University is there to deliver a service called postgraduate training / PhD programme.
For this service, it receives money in the form of the tuition fee.
The student does not have to "give" anything to the supervisor.
The student's contract is with the university.
What the supervisor gets is between the supervisor and the university, not between the PhD student and the supervisor.
What you are saying regarding the supervisor-student relationship being a "one-sided transaction" is like you are paying a company to repair your windows, the company sends their workers to do so, and then the workers don't do the job (or do a poor job) because it's a "one-sided transaction" and they "don't get anything from you".
Now, I do agree that the supervisor should get something out of this tuition fee - in fact, I am deeply concerned and I very much agree that academic staff around the world, even in developed countries, are seriously underpaid - but that is an issue for the supervisor to raise with the university, not with the students.
What you are saying is simply unrealistic (as far as the PhD student is concerned) and no PhD student should ever be concerned (or has a duty to be concerned) with such aspects.

(Continued - Part 4 - this is the final part - I am sorry for multiple replies but findaphd.com does not allow me to write more than 3000 characters per reply.)
A term that you may find surprising (such as your supervisor being allowed to forbid you to speak to experts in the field) must also be emphasised to you appropriately and sent to you in a *** durable medium *** (this is where MOST UNIVERSITIES FAIL, to the best that I can tell).



"4.42 The CCRs require you to give confirmation of a distance contract using a durable medium, within a reasonable time after the contract is entered into. The confirmation must include all the pre-contract information, unless it was already provided on a durable medium. A durable medium is defined in the CCRs as
Paper or email, or any other medium that:
(a) allows information to be addressed personally to the recipient,
(b) enables the recipient to store the information in a way accessible for future reference for a period that is long enough for the purposes of the information, and
(c) allows the unchanged reproduction of the information stored.44
An example of a durable medium would be an email with documents attached, which the student can retain and use to access the documents at a later date. A website link would not be a durable medium as websites may be changed and so would not be a permanent record of what the student had been given.”

Please see the documents at the CMSA link below. I would strongly recommend that you read it carefully and compare them with what is happening to you in your PhD and also with your PhD contract / offer letter.
https://www.gov.uk/government/publications/higher-education-consumer-law-advice-for-providers

(Continued - part 3)

I can feel from your post that you are very seriously impacted by this, and you have every right to be.
I would recommend talking to the OIAHE about this - you can phone them directly, your university doesn't have to know.
The OIAHE will likely require you to show that you have first tried to use your University's internal complaints procedure, unless you have a very good reason not to do so, e.g., you feel very intimidated.
I would personally feel very intimidated in your case.

Some questions you may wish to investigate are:
I would ask myself "if my University has a properly-working complaints procedures, then how come they employ someone who behaves so unprofessionally?"
Does your University has a way to regularly check the professionalism and behaviour of their academic staff (including the level of skill they have in their field)?
Is there someone in your university who is responsible for such checking?
Is there any documentation for your PhD (e.g. PhD offer letter, other accompanying documents etc)?

While you are a postgraduate student, the CMA (the Competition and Markets Authority) has produced documentation focused on the consumer rights of students. It is mainly focused on undergraduate students, but since it deals with consumer rights it is likely that there are many cases in which consumer rights still apply to postgraduate students too. For example, since you are self-funded, you are paying a tuition fee (right?), in other words you are paying for a service called PhD programme, which makes you a consumer.

***** Please do seek further advice on this matter and don't take my words for granted - e.g. talk to your University student union or similar (it may also be called some other names such as "advice place" etc), or even from solicitors.*****

*** Everything that your supervisor requires you to or does not allow you to do must have a contractual basis.***
Your supervisor cannot ask you to do something (or forbid you from doing something) based on things such as "I am the supervisor and I say so".

Now, in the UK, a term in a contract (including a PhD offer letter) must be ENFORCEABLE. In order to be enforceable, it must fulfil certain requirements - such as being open and fair. Openness and fairness are defined in the law and explained in the CMA guidance (e.g. CMA 37 - google it).

**** People often make the mistake of thinking that just because a term is written in a contract (including a PhD study contract / offer letter), then it "means" they have to abide by it. IN REALITY, IT SIMPLY ISN'T SO. A term, even one that the student willingly agreed to, may not be enforceable if it is unfair. ****

(Continued - part 2):
Now, my personal opinions:

It sounds like your supervisor is an "impostor with lustre", i.e., someone who does not really know their subject (and perhaps aren't that smart either) but puts on an appearance that they do.

Avoiding inconvenient situations by being silent or giving terse / unelaborated answers is a typical way of reacting for incompetent or abusive supervisors, of which they are quite a few from what I can tell.

Think about it (if what I suspect about your supervisor is correct):
If you interview those experts, then it will be IMMEDIATELY seen, by comparison with them, how little your supervisor understands / knows in the field where she is supposed to be an expert.
If she tells you why she says "no", she will have to either say an obvious lie (i.e., give you a false reason) or say "I don't want you to talk to them because, if you do so, you will immediately see how little I know in my field compared to them" (how many supervisors would admit that)?

I really don't think you are a "problem child" at all. You want to talk to experts in order to progress with your research. This should be commended and highly encouraged. Why on earth would you blame yourself for this?

Now, the "lecturing time" - apologies in advance if you are not going to like what I write here:
I would like to end on a positive note so I start with the negative first:
1) The only "problem child" matter I can see from what you wrote is "I am not to proud to be wrong". If you are wrong, then you must admit it. There is no point arguing that the Earth is flat. Think about it this way: your primary supervisor may be behaving towards you in this way precisely because she is "not to proud to be wrong" too. Do you like the effects such an attitude (on the part of your supervisor) has on you? What you have inside yourself HITS others (i.e., it impacts upon them, sometimes very seriously), even when you don't realise it.
***Whether you are a student, a supervisor or have some other role, t is an extremely big problem in research of any kind if you don't feel perfectly comfortable being wrong when you truly are.***
2) However, having said the above, your supervisor should truly prove that you are wrong. She should definitely not say "it just is" or other similar replies. If she has scientific arguments that are well-supported by evidence, and based on them she proves that you are wrong, then that is something good. But to interrupt you like this, and to leave you without feed back, is very wrong and very unprofessional. Quite frankly, I wonder why your university even employs her.

Based on what you wrote in your post, I would say your supervisor is extremely unprofessional and, even more, what she is doing to you is bullying and harassment - albeit in a somewhat "subtle" manner.

Hi Nicmcc23

I am sorry to hear you are having such difficulties and I truly feel for you.

If you are studying in the UK, sadly, yes, ***in the short run***, she can force you to do a lot of things, in various ways - few of them legal, but who cares. This is because UK universities, especially at postgraduate level, are often somewhat like "no man's land" where supervisors are allowed and even enabled to do whatever they want irrespective of relevant laws, policies etc. When you look at the laws and all the documentation by regulators (OIAHE, CMA, QAA, UKRI, Office for Students), you would say that universities in the UK are well regulated and so on. But just look at the PhD horror stories on this and other forums. How often are these laws and sets of documentation followed in practice?

*****BUT, please do not be discouraged*****.

In the long run (i.e., it may take more time), and depending on your circumstances, you have of course the option to go to the OIAHE (the Office of the Independent Adjudicator for Higher Education), or even sue your supervisor / your university if you have lots of money for lawyers or are insured for lawsuits.

If you are not familiar with the OIA, you can read more about them here. You can also call them on the phone - be calm and polite (I know it may be hard to do so if you are distressed by your supervisor).
https://www.oiahe.org.uk/

However, you should know that neither you or your university have to abide by the OIAHE's recommendations. In other words, you can write an OIAHE complaint, your complaint may be successful (justified) but even so your university may choose not to do what the OIAHE says (the OIAHE call the outcome of complaints "recommendations"). However, that said, it is very rare for a higher education provider not to follow the OIAHE recommendations.

**** If you want to go the OIAHE route, please do submit your complaint to them as soon as you can - this is very important. ****
The more you delay, the harder will be for the OIAHE to implement any practical remedies (such as ensuring your supervisor allows you to do research properly, to have the exposure to experts in the field that you desire etc.

Please do read carefully the information on this webpage:
https://www.oiahe.org.uk/students/how-you-can-help-us-to-review-your-complaint/
Please also do read carefully the information on this webpage too:
https://www.oiahe.org.uk/about-us/reviewing-complaints/what-happens-when-a-student-complains-to-us/