I see a lot of people complain about how hard the game. And I know how hard it is in the early, especially the first time meet Lu Bu.
But if you want to play the game easily, just progress the story until you unlock Anepic (it's a late game dungeon tho) or there is another option for leveling in a little bit early game. Progress until you unlock Amor (mainly dungeon for dona dona tho).
If you can beat this dungeon easily, continue your progress until you unlock Industry Plz. You can leveling here before Anepic.
Of course the leveling part is annoying. But, if you can lvl up some key characters into lvl 40-50 you can beat the game easily after that.
PS: I only focus on Kikuchiyo. Just save all item (MP and VP) for her + PUT -mp cost badge.
Beside her, I recommend Tora, Antena, Kira (since they have AOE skill), and Zappa (if you need Tank)