True. I guess my point is that there isn't a statblock for it and you can only encounter an actual deity in their divine domain. But they effectively write the rules of that layer of their plane, or their demi-plane, so it's kind of wild to try to figure out what they can't do.

Tiamat might be the only one that's feasible because she lives on Avernus but doesn't rule it' she's imprisoned in hell. So she can probably only warp the area right around her. But even her aspect's stat block is CR 30 so who knows how you'd run her.