Chapter 20

Alright so I’m approaching chapter 20-31 and even with the three nikkes with the three time use per day limit I am now finding myself struggling to beat some rounds/enemies. I currently have two characters leveled up to 200 with not fully leveled up gear. But what I’m really asking for is there a more efficient way to level up my characters? At the moment leveling up one completely to the 200 cap is so expensive that I can really only do one maybe once a week after hoarding materials every day.