Linux

Libreoffice is strongest when you're using ODT format because it's an open standard. It's not at all their fault for docx incompatibilities because they change the format CONSTANTLY and of course their only documentation is internal.

Personally I haven't had those issues though, only slight formatting differences when opening docx files, and half the time it's because I didn't have the font installed. You can change to the ribbon style if you really want but personally I prefer the older style, I find it's easier to find what I want.

No issues as long as you switch the toolbar to use tabs or contextual groups instead of the insane button overload which is still the default for some reason.

I use Word at work and OnlyOffice and it works perfectly fine for my needs.

I don’t see any reason to go back to any proprietary software at home 😇

I've been using libreoffice for several years, and when I have to cowork with someone, compatibility issues always happen. However, since last year, I've been experimenting transitioning to onlyoffice for a few academic works, and it has been so smooth. So far, I opened all documents people sent me without issues, and published some works, and no one involved in the process complained about anything. If you need compatibility with ms office, I suggest using onlyoffice. It's also foss and can be used at most OSes, even on android.

Edit: I see that other people already suggested onlyoffice. I didn't mean to sound like those pushy comments that appear on our inbox from people saying the same thing again and again.

This is another state, last one was Munich