bethesda intensifies.
Seriously, it's always been the same since the first Divinity, early game is great - mid and end game is a walk in the park.
Hell, in divine divinity there was like 3 bosses capable of killing you in the entire game.
I'd recommend self restriction over your build ... don't learn healing spells / don't let your elemental resist go too high ( I personally keep the lvl 1 sarong for the entire game ) / use only 1 handed sword without shield / only disarm traps with the disarm kit ....
And don't use your spells or potions before the fight start.
Larian's games can be a lot of fun despite the lack of lategame difficulty, it's all about the roleplay.
Sorry for my english.