I've assembled and done editing passes (back and forth to an editor, using comments heavily) on two 200+ page novels in LibreOffice with none of those problems,

I've assembled and done editing passes (back and forth to an editor, using comments heavily) on two 200+ page novels in LibreOffice with none of those problems, so it sounds like something in your doc must have hit some specific edge cases/bugs. Not doubting you - I find it clunky and fully believe there's bugs there too. I did most of my writing in Google Docs, but chapter by chapter both because I find it easier to keep individual chapters separate and because Google Docs certainly can't (or couldn't, anyway) handle anything approaching that size without slowing to a crawl, but it just felt better than LinreOffice for the actual writing.