GoldFinger
Just an idea, for the biggest fight he has ever fought, make it him against Rick Sanchez. The man he took his genius from coming for revenge and make sure nobody is safe, even his kids. I think Rick Sanchez needs a comeback, especially when he last appeared was when he was just a consciousness in his mind. If you can do that it would be great.
another thing. seeing how the bifrost is being an annoyance, couldn't Jay just make a giant portal and just move all of asgard into a micro verse as well. don't even need to push stuff in, just move the portal into the stuff. litteral planets and solar systems just Portaled away into a resource collector microverse.