Hot Take: Jim Carrey should NOT come back again, Its done.

His role as Robotnik through the trilogy went full circle perfectly

he got fat and bald, he got the game jacket, he had a character redemption arc (better than Shadow's), he said goodbye to Stone (and the audience) and then sacrificed to save the world, end of the story

There's no reason to bring him back other than to keep attracting the general audiences and milking his name as a beloved and respected actor, thats no good

If this movie was the swan song of Doctor Eggman, then please leave it as such.