This show sounds great on paper. "Watch a bunch of stereotype anime cliches fight each other", "why?", "cause why not!". If it had just been that it could have been actually worth watching, but the show got so caught up in trying to have a "serious" story that it basically shot itself in the foot before the race even started.
You have a fun premise. A fun, dumb, entertaining, "popcorn movie" type premise. Failing to add depth or artistic merit hurts your show more than not trying to add them at all.
It's kind of like when you go to see a Godzilla movie and then they show you scenes of the government talking, or some bs about war or family, like... stop. We all know why we're here. We want to see the main characters fight, stop trying to make it something more than that, you're doing a bad job at it.
If it had taken itself far less seriously, it could have been actually good. There's nothing wrong with deriving fun off seeing archetypes interact, to be honest, that's half of anime anyway, but when you spend so much time on useless bullshit that doesn't specifically help the MAIN REASON your show is fun to watch, it ends up ruining any potential the show had at being worth watching.
TL;DR:
The show spends so much time trying to have a "serious" story and failing to make compelling characters out of archetypes that it forgets the point of the show is to be a dumb, enjoyable, popcorn-movie type premise piece for the sake of brainless entertainment. They tried to make something smart out of something brainless; it didn't work.
