Recommended difficulty?

I opted for the medium Expeditioner difficulty, and I’m not far in, only in the Flying Waters with Maelle. I’m really liking the combat system and I get a lot of cool ideas on chaining skills together for huge damage, however, nearly everything dies in 1 turn for me, and I almost never take damage. The only moderately tough enemy was a green boss guy in the very first area who had attacks that 1 shot Gustave and Lune.

Will the game get naturally tougher where I need to use combos and actual hit dodges and such, or should I bump it up to expert?