Meta requesting NDAs to discuss P92 means literally nothing. I once signed a NDA with a prospect (not even a client), and the whole thing unraveled in a very nasty way when said prospect showed very little respect for my work. The fact Meta wants people to sign NDAs to discuss a not-yet-public project is no grand conspiracy to kill the Fediverse. It's literally just how companies work.
More generally, the discourse over Meta joining the Fediverse is beyond irrational. People are discussing rumors as if they were facts (is there any evidence that Meta has offered payments to Mastodon admins?). They hypothesize and catastrophize everything. What about facts and reasonable hypotheses?
I'm not trying to defend Meta here. I don't trust them, at all. But not trusting them, and inventing an alternative reality, are two completely different things.