Don't worry, from what I skimp they gonna get boost. Either crit chance or crit damage boost mostly though. And I do understand how they can struggle in some harder map. Dendrobium sweeper team has some hard time with 800k+ stage as well since she can't take boss down in first turn. Luckily though pests in the map hit quite weak and far more forgiving than.. like Kodaibana or broken AS stage. (Can't confirm how they will fair since these stages don't allow helper though)