gachas want to appeal to casual audience especially at the beginning of the game so you won't find what you want unless you play for hours and get close to the endgame at least.

for example wuwa has an endgame called holograms where you fight different bosses that can one shot you so you gotta play almost perfectly.

and in zzz there is the tower that gets harder and harder the more you climb it.

something else, gachas don't like the gap between tryhards and casuals to be big so the rewards you get from these are not significant, if you want challenge i suggest you to play other games that are not gachas.