I'd say the health of the bosses is balanced for the gear you're intended to have while fighting them.

And you can't really account for people cheesing the bosses with bow/arrow spam from a safe place, or building cover structures or glitching the bosses in place.

I also don't think that using the dodge mechanic to dodge boss attacks should be seen as something negative.

All the bosses in Elden Ring are easy.. Once you figure out the attacks.
The same goes for Valheim.

Though I agree on the AI, I feel like most of the time the bosses are not really trying to get me, some of them are a bit too slow, movement wise. Sometimes they get stuck on stuff.

Damage, Health and Attacks wise though, I think they're just fine as they are.
It's a challenge with normal gear, but can be made easier by grinding and prepping more.