I've reached level 150 on Cresselia and it has gotten more difficult, to the point where I'm having to buy either a Disruption Delay or Mega Start to comfortably beat the level, but I could probably brute force it without items if I kept trying.
Either way, 50 stages in 5 days should be doable even accounting for having to grind for coins.
Either way, 50 stages in 5 days should be doable even accounting for having to grind for coins.