I did not read the link, but two of my biggest concerns do not appear in the summary you provided :

• the burden of hosting an ActivityPub enabled service is often duplicated for each instance instead of being split between them (for example, my Lemmy instance has a large picture folder and database because it is replicating all posts from communities I’m subscribed to)
• it’s a privacy nightmare. All instance admins now have as much spying power as the single centralized service it is replacing

(Edit: typo)

In my experience, OnlyOffice has the best compatibility with M$ Office. You should try it if you haven’t

2 years ago was already amazing for someone who tried to play CS 1.6 and trackmania using wine 18 years ago