Honestly I think if they were to fight each other I’m putting main universe Diego on top extreme diff. While it’s absolutely certain that a lot of the things DIO did in his brief stint in the manga were incredible feats he did them usually with external tools. And while his stand The World is also incredibly strong, it lacks range, and can only stop time for 5 seconds, which could be crucial but I think Scary Monsters is just too overwhelming and Dinosaur Diego would just be too fast and brutal for DIO.

Tw would be around sp power levels, idk if that applies for au too. And tw is definitely stronger than sm and timestop of 5s is enough for tw which is faster than light.