That wasn't a quick solution at all. It was a last ditch effort.
Regardless, Prime's thrown planets around the universe like ping pong balls. He's wrecked nearly every noteworthy hero on DC earth at less than full power. He's shit stomped the collective LoSH. He's casually swatted Superman away (heck, Supes himself outright stated he could not stop Prime w/o help.)
Listen, I'm not denying that Superman has extremely uber feats, but considering the above (and more) I don't really see how it can be argued whether or not Prime is >. Imo, he has always been portrayed as significantly more powerful.
Pretty much and using Flash as an indication that Supes can hang with Prime is foolish. Flash was blood lusted when he faced Prime...Supes or Supergirl never faced a Flash that was in a serious mode like that.