How does this scenario work in a web-only situation?
Like OP I too am a long time *nix + LO user, having to work daily with other MS users. What I see in my professional use case is that, yes, those web versions of Word and Excel do work, but they also have significant eye brow raisers. First of all, since you are not a MS registered user, you do need to jump through 10 million hoops to get to the application to begin with. IMHO MS did a master stroke there, applying the EUs 2FTA requirement to serve their own use case and make it way harder to enter their walled garden (MS Authenticator). Some that come to mind immediately: web versions do not have all options/ capabilities of local versions. Seamless portability between local vs web MS applications can be troublesome and require extra work infile. And this one that makes me roll eyes every time: the MS window dressing about file compatibility. If you have a file in on-line versions of Word, you can File > Save as > Download
them as an open document. But, if you then open this ODT locally with LO, it looks like nothing you exported out of Word. If you have an ODT and you upload it to the SharePoint of the people you're working with, and open it in Teams/ Word/ Excel/ PowerPoint(web version) you will see... nothing. You can do... nothing. Upload and double click your (LO exported/ native) Word, Excel, PowerPoint, what ever file, and it opens and you can view and edit. PDF, no issue at all.
I agree with other commentart here that LO improves every time in its compatibility with MSO. It's a one way street however, because at the same time MS does what is best for MS with all this open document window dressing/ camouflage being just enough to serve it own not so open, "why don't you just use what you're supposed to use, we are the industry standard" needs...