Called it. I said this last week when everyone was still hysterical about blocking Meta:
Everyone is talking about defederating preemptively because of XMPP and EEE. But the very fact that we know about EEE means that it's much less likely to succeed.
Zuck is seeing the metaverse crash and burn and he knows he needs to create the next hot new thing before even the boomers left on facebook get bored with it. Twitter crashing and burning is a perfect business opportunity, but he can't just copy Twitter - it has to be "Twitter, but better". So, doing what any exec does, he looks for buzzwords and trends to make his new product more exciting. Hence the fediverse.
From Meta's standpoint, they don't need the Fediverse. Meta operates at a vastly different scale. Mastodon took 7 years to reach ~10M users - Threads did that in a day or two. My guess is that Zuck is riding on the Fediverse buzzword. I'm sure whatever integration he builds in future will be limited.
TL;DR below: