What's worse; a game that is Too Easy or Too Hard?

You can get good enough to beat a game that's too hard. You can't get shit enough to get appropriate difficulty out of a game that's too easy.

However, it depends a lot on the intended experience. The core loop of Souls games ultimately is to overcome challenges, so with no challenge that loop falls apart. That's very different to the intended experience of the Persona games, which despite being pretty easy worm their way into being some of my favourite games. This is different yet again to something like Satisfactory, where the "challenge" isn't in doing something, but doing it efficiently as possible.