Old King Thor has some solid feats that say he can most definitely hurt SBP if he gets cocky.
Also two mjolnirs can big bang SBP's noggin if it gets rough. The countless distractions and berserkers created by Gorr, giant, cosmic storms, planets and red sun's being hurled will cause enough chaos that a portion of Primes speed advantage will be negated.
SBP is still a beast. It won't take.a few seconds before it's OKT w/2 hammers+ Gorr w/necrosword vs. him, and if Gorr falls it's OKT w 2 mjolnirs, Jarnborn, and the Necrosword.. Prime ain't beating that though.
Team 6-7/10. If Prime takes out OKT or Gorr from the get go that team is done. Regular Thor's can barely hurt him.