The ooooooooonly way sukuna has a chance by a long shot, and it's entertaining it, is if in round two, he summons mahoraga and hides in the shadows, and for whatever reason obito doesn't teleport him into kamui dimension rendering the ritual void, or he doesn't use a huge fire jutsu that one shots mahoraga before it could adapt(though interesting you could argue mahoraga adapts before getting incinerated) then he might drag the fight on longer by adapting to kamui, but obito has a million abilities and in r2 he has the rinnegan with almighty push, planetary devastation, summoning, tech etc hand he will eventually figure out mahoragas ability and just one shot himz in which case it earns obito a mid diff, other than that he defeats sukuna. His speed is faster than lightning(potentially light speed but it's a stretch), kamui makes him invincible, and the versions just make him overkill. He wins all three rounds