I’ve seen that some instances have already done it preemptively.
Which is irrational. Threads already has five times more users than the fediverse. There’s literally no reason for them to waste time trying to harm ActivityPub. Personally, I won’t be surprised if they shelf and ultimately cancel their plans to implement ActivityPub because there’s literally no reason for them to waste their time, especially when everyone in the community is throwing shade at them.