A growing number of instances (mainly of Mastodon so far) are signing an ‘Anti-Meta Fedi Pact’, pledging to block any instance owned by Meta in the fediverse.
I don’t know how big this will get or how effective it will be, but if you run a fediverse instance, you should take a look at this https://fedipact.online/
They could well try to pull the classic “embrace, extend, extinguish” move. Appear to embrace an open standard, then start writing proprietary extensions for it, and then use their clout to get everyone to stay on their network and abandon the open source version (because everyone’s on Meta’s network)