Hi wowzers, I totally understand you! Writing is like crunching a book :)
Also, I sympathize you regarding problems with supervisors. Sometimes people are egoistic, and we need to be as well. I find my 2 sup is more helping, and now I do see and consult my 2 supervisor much more than my first. Perhaps, my first sup is not bad (could be simply misunderstanding), but I often find their comments confusing or that I need to do more work and look at something else, whereas I often just need to finish what I already have (and my 2 sup helps with this). When my 2nd suggests something to do, I know that it will help.
I have started to use those writing services at uni. I found the right person (few others were useless), and have writing sessions with them. Surprisingly, they understand the research I do, and can help with structure, phrasing etc. Not only these sessions help international students, but any students. After a morning session with them, I am happy and energised.
So my advice is to be more selfish and use any strategy, which will be more efficient in your case.
Good luck!