Yeah but
He is not sure but he would beat him his CT is inferior to Gojos,without Mahoragas adaption he would lose against UV.
No, because in his true form Sukuna (10 ft tall + 4 arms) would have a much greater advantage in the hand-to-hand in the domain battles.
Remember, it took about 3 minutes for Gojo to damage Sukuna enough for malevolent shrine to collapse, and at the same time unlimited void got destroyed by malevolent shrine. Their domains collapse at the same time.
If Sukuna can do literally anything that makes him last
one second more inside the domain than he gets a win con.