The big journals have journal finders that can suggest journals for you.
https://journalsuggester.springer.com/
https://journalfinder.elsevier.com/
https://journalfinder.wiley.com/search?type=match
https://authorservices.taylorandfrancis.com/publishing-your-research/choosing-a-journal/journal-suggester/

I don't much about South Korea or their university system, so this advice may not be relevant.
I disagree with your supervisor, in that you don't need to design very experiment in your thesis. I think doing the labwork, analysis and writing should be enough. However, convincing your supervisor otherwise might be difficult. Talking with your second supervisor or another member of the faculty for their advice would be a good idea. Maybe that is the standard expectation in your university or that your university has clear procedures on how to deal with it. If you do have to do the extra experiments you should be explicitly clear that you want to finish and will only do work that will be included in it. He will stop treating you like a technician when you stop letting him do it.

Is there anyone in your department who you can talk to like another lecturer or the dean? They might be able to give you advice on how to use the university system to force a submission. Otherwise you could talk with your students union about your rights and possibly file a complaint against him. As 13 first name publications is a significant contribution of knowledge that most definitely is good enough to submit.

Are you in the UK or USA?

Congratulations on passing your viva Dr Ericca!
Finishing your PhD is a big achievement, so don't put yourself down. I understand you are worrying about your future but you should put your achievement in perspective. Passing your viva is not easy and you have obviously done well.

Now, sorry to be blunt, not everyone can become a lecturer. It is hard to become a lecturer and even harder being a research active lecturer. Academia is not a fairytale job and lecturers are just as exploited as industry employees. There is nothing wrong going back into the real world having gained invaluable experience, so don't be ashamed if you do. Saying that, if you are passionate about academia, there is nothing wrong trying.

A paper is still a paper. You might not agree with the conclusions but if the data was collected correctly it is ethically okay. Your reviewers cannot deny that you have made a novel contribution of research, which is the main aim of thesis. If you feel uncomfortable defending the work, you can just agree with them and say that further work is needed but it was outside of your scope. Nobody's thesis is perfect, you just need to do enough. So I wouldn't beat yourself up about what you could have done and look at what you did do.

I haven't submitted yet but have been feeling the same way recently in my 4th year. I have lost all love for my work in the last 6 months and I can only cringe looking at one of my papers. I think that everyone goes through a stage near the end of their PhD where you are just worn out and need a break. Spending so many years on one topic can destroy your passion but it is nearly over. I would just defend your thesis to the best of your ability and then you can forget everything about it.

Goodluck!

Congragulations on your baby!
I don't have any first hand experience but worked with a PhD student who had a baby during her PhD (and passed). Generally PhDs are very flexible and most supervisors don't care when or where you work, as long as you can get the work done. I would say most supervisors are somewhat understanding and you will have strong university protections if not. So there shouldn't be any major issues.

I would say it is fairly common in the UK. The university should have no issue with it but you could probably check with you graduate department about the technicalities, but I think it would be fairly easy. However, do you know if this mathematics lecturer would want to supervise you? You don't have to limit yourself to people who previously worked at your university but it could anyone that gets along with your main supervisor.

You do not need your supervisor's permission to publish a solo author publication. Seriously, if you believe in your work you should seek validation from the academic review process and not your supervisor's opinion. Your supervisor sounds toxic and I think you shouldn't let him get into your head. You already have two papers from the sounds of it and have won an academic excellence award, you are good! So don't let your supervisor get to you and start plotting an exit route. If you submit the paper without his name on it and it gets accepted in a decent journal (preferably one that he has published in) it kinda of makes his opinion moot.

On another note, I agree with trevalda, it would be very good to talk with your second supervisor if you have one. Just be honest about your opinions and that you think it is a worthwhile piece of research essential to your PhD. Listen to their suggestions and see if there is an easy compromise that everyone can agree on. You could also talk with your independent reviewer or someone in the graduate department about your issue.

It is difficult to say without knowing your supervisor first hand. Though can you wait until your PhD is nearly done (and thus don't need your supervisor) and then submit it as a solo authored paper. You can simply tell him that if he doesn't agree you will publish without him.