Cap'n Kobold
Hero
Indeed. I'm not getting "as powerful as someone who can cast Wish and many other effects" vibes here.The problem is that they're fighting some challenge rating 1/4 mooks here. Level 20 D&D characters need to fight way tougher things. Those mooks almost managed to take down Batman here, had they been trolls, let alone goristros, he would have been batpaste.
I'm not even seeing much indication that Batfleck and Arrow are much above 5th level to be honest.