I've tried to balance the opponents, especially after the beginning, to be challenging but fair. I didn't get many complaints about difficulty in the demo, but I have changed some scaling since then and I switch the LLM, which could lead to more difficulty.
I'm grateful to hear any feedback and will rebalance if any boss seems consistently too difficult.
That said, these suggestions may help:
1) Don't spend too much on research. There are diminishing returns and you need most of the points for stats.
2) You may have a poor stat distribution. Consider what your strategy will be in the fight, what stats you need to execute it, and complementarities between stats like Huanjing and Endurance that reward some allocations much more than others.
3) This game is really built around reacting to your opponent's ability. I let you discover that ability through research or trial and error and allow you to choose a new ability each fight, so a big part of the intended gameplay loop is figuring out how to hard counter your opponent. Every opponent has better stats than you so you need your ability to give you an advantage over them. In every case except the final boss, who adds another layer of challenge, you can shut down their magic or turn it against them with careful ability choice and roleplaying.