Apps assigning new users randomly to a good general instance (vlemmy.net, lemmy.one, lemm.ee etc) eithout requiring the user to know about instances,
This is a terrible idea, and the defederation of Beehaw is the exact reason why this is a terrible idea. Don’t get me wrong, with the attitude of the Beehaw admins I suspect that Beehaw will constantly be defederating from a lot of instances over the course of its existence, but this comes with the consequence of people suddenly being locked out of participating in their chosen communities because “you signed up on the wrong instance.”
Which is something nobody should have to experience.