The only who ever really gives Billy like a set "limit" is Tini Howard the way she does it through annoys me it's like he does x empunt of warps for the day & he's just done which has never really been the case for Billy, like I highly doubt Ewing will write him like that, so other than that I would say no with the exceptions of writers needing to nerf him for plot purposes I don't think Billy really has a limit outside of what he thinks he's capable of he limits himself for the most part.
Also about Billy & Tommy's mutant status I really hope that gets addressed this year the speculation is annoying. Tommy was on Krakoa in seconds either he ran right through a gate or directly to the island, if he were human the gate wouldn't work as shown in Children of the Atom but Leah left the whole thing obscure & she lowkey told everyone she would address it I hope some writer has the balls to actually do it maybe in the Guardians, SWORD Crossover it's a yes or no question not that difficult.