When I open my Word docs in LibreOffice, they still look significantly different than in Word after all these years. In OnlyOffice they look exactly like in Word. So it replaced Word-in-Wine for me.
Huh, I've not had that issue with the documents I've worked with in the best part of a decade.
What is it that's different for you? Page layout, text wrapping/length, image support, table formatting? Something else?
What platform are you using, and if you're not on Windows do you have the equivalent-metric Liberation font families installed so that docs which rely on non-redistributable proprietary Microsoft fonts can be rendered properly?
https://blog.documentfoundation.org/blog/2020/09/08/libreoff...
I remember also looking at WPS Office for this and it seemed mostly okay to me: https://www.wps.com/office/ (though no source code available, at least it doesn't seem so)
Then again, LibreOffice feels like the most trustworthy option out there for me (and is the default in many Linux distros), so I ended up just using that, any drawbacks and all. Nowadays I use LibreOffice on all my computers and have basically gotten rid of MS Office altogether. If I ever need to send someone something that looks consistent across all devices, there's PDF/A.
I've actually used PDFs for presentations as well with no issues, especially after the inconsistencies of LibreOffice Impress and PowerPoint made one of my past presentations look like an utter mess on someone else's computer (fonts/locations were all wrong).
The protocol that connects the office suite to the file sharing platform is called WOPI (https://en.wikipedia.org/wiki/Web_Application_Open_Platform_...). OneDrive/Dropbox/Nextcloud all seem to support it.
Seems like Collabora and OnlyOffice are the two big players right now.
There have been various efforts to bring LibreOffice to the web, but I haven’t tested anything in a long time, so I can’t say if it works well.
But those are reasonable answers. I would rather see engineering effort go into fixing bugs in the suite, but I realize that the people volunteering to "Web-enable" the software aren't necessarily the ones who'd be fixing unrelated bugs.