CHEESE COMP OR GIT GOOD VS DUOLIST

I've been playing Duolist for the last week.

trying different comps. grinding for better pictos and lumina.

yet the outcome remains. I can comfortably beat first phase. but second phase ends up similar everytime. dead within 5 turns.

I am slowly beginning to think I need to build a Super build like you see on YT to beat them. but doesn't that take the fun out of the game?