I have to say, after playing with Core, it's not as hard to me as people have made it out to be. At the same time though, I have the power of beta foresight, and I've been watching my DM going in blind and getting destroyed with a much less optimized party setup. It's... Undeniably overtuned without significant min-max. Like it gives me the impression that it's balanced for the assumption that you're going to be going in to each boss fight almost fully buffed to the max at the very minimum.
A couple enemies really need a balance pass. Especially the swarms in chapter 2, and the plagued tigers or somesuch with +22 bonus to hit because fuck you that's why. They have counters but they're so specific that it's only really one step removed from telling someone to just high ground stealth ambush in BG3. It's probably worse here because they chose to adapt the one AP involving enemies with across the board resistances or immunities to damn near everything early on. I've been hitting delay button a lot and waiting for enemies to come to me too, because walking up to them with only one attack while giving them their full attack is a whole lot worse than the other way around.
On the other hand, the enemy AI is now starting to threaten my back line much more often. Maybe they just made the AI dumber in chapter 1 or something.