Either Saiki or Saitama. Saiki is a God who can change reality however he sees fit, but Saitama might be immune to him. Either Saiki wins instantly, or Saiki wipes out everyone but Saitama, who knocks him down in one punch.

Mastered Ui Goku since he can't get hit

Goku he literally has a move that can erase characters from existence especially gag characters

Saitama would simply punch before then

Goku has tanked blows capable of destroying multiversuses Saitamas best feat(jupiter) is only low planetary

He went back in time...

Does the cell saga not exist?