The more I read, the more I am in the camp of "let's not." Meta has rarely acted in the best interests of its own users; from their unethical experiments into causing depression to their privacy issue to... well, everything, they are classic examples of bad actors. The fediverse is not secure enough or big enough to counter Meta's takeover if we open that door... there's a reason we're in the fediverse and not the metaverse, after all.
The decision of whether to federate is up to the individual instances, and I'd not want it any other way. But I do think we should be encouraging instances to hold off on Meta-fying. Else, we'll be fighting Meta in a game that they're much better at than any of us are ever likely to be.