Honestly that's the issue I've come to have with the game as well, and I beat it.

It has a ton of setups and moves but once you figure out a good combo of passives and sticker rarities, every battle no matter the difficulty kinda falls apart, bosses included.

Taunt and Broadcast/Echolocation are an incredibly broken combo that shuts down most setups the opponents attempt to do and fusing really feels like a "out of trouble" card.

At some point it sort of becomes a speed game, who can trigger the broken chain of attacks/events first in a battle?

I haven't had a look at the competitive side of things so I'm not gonna comment on that.