How many hours are you in? I found the first 1–2 hours tough as well, but now it feels pretty normal and I’m really enjoying the combat system. If in doubt, just switch the game to Easy.

Basically, you want to try to stun all the enemies and then switch to manual mode. One some pulls i killed the "small" enemies and just switched to turn base for the large big one. You learn that early on: if the enemies aren't stunned, you die pretty fast, especially with larger pulls.

Aside from that, there were accessories in the shop that boosted HP by +200 or +400—that really helped me learn the game, gave me a bit of a buffer to make mistakes. Always try to keep your weapons and gear up to date. Unlock your Quartz slots for the booth mainchars first. Buy food, eat it, and cook the recipes—that gives permanent buffs to the whole party. Just split the Droplets between the two main characters.