I enjoyed Nioh 1 quite a bit, until the last roughly 10% of the game, plus the DLC. I felt like the game took a completely unfair difficulty spike at that point that I could not get around.
I was therefore on the fence regarding Nioh 2, but ultimately bought it and tried it and hated it. I felt like it reached Nioh 1's endgame difficulty within 4 or 5 hours.
The big issue I have with these games is all the fucking particle effects, I.e. the "Yokai realm". It's just a bunch of visual noise that my brain just can't parse. As such, I never got a good understanding of hit boxes or dodge or parry timing. And one mistimed dodge or parry means you lose like 80% of your health immediately, if not being out right killed. I have the same complaint about most of the bosses in the Elden Ring DLC.
This series is not for me.