If it's just the organized crime villains me thinks he can do it. Intergang will take him a while though.
I think Intergang could even potentially too much. I wouldnt debate too hard saying he'd lose to them.
But, if Lex and Metallo and the like are in this, then Frank is dead.
I agree. Intergang is iffy. He could possibly take out Metallo from a mile away. Just needs to get his Krypto heart. Same with Lex but Lex most likely has a life of thick bulletproof glass. Especially once the gang slaughters begin.