My hot take (and probably shitty opinion) is that the barrier of entry will filter a lot of the noise.
Those that have the ability to directly contribute already know how to do so, know how to see what’s already been raised, see what’s in progress etc.
GitHub centralises the issues, has full tracking of the processing of those as well as any relevant discussions.
Anything on the fediverse for that would need a lot of work to keep it reconciled with GitHub activity, and would more likely just be a place to placate users.

Once this influx of users cools a bit, once the development can slow a bit, and everything left are big issues… Then yes, I think somewhere for everyone to discuss and get involved is a great idea