Prince of Nothing is one of the grimmest, darkest series I’ve read lol
Lots of atrocities committed in the name of religion, power, etc. Lots of visceral depictions of pretty serious subjects. Lots of philosophizing about pretty dark things.
Through it all though the characters are compelling and the story is engaging after a point. The world and characters feel very real, even some of the more outlandish ones. There’s certainly no “fun” in it like there was in the First Law books. I get the sense that it probably goes way too for in the grim dark direction for you, regardless of how well it’s written.
Not to be that guy, but Malazan strikes the perfect balance for me between a grimdark feel and a hopeful theme with fun characters. If you haven’t read it and have the time, those are always worth picking up.