Yeah Gloomhaven left me exhausted, too.
Plus, I'll be honest: the main card selection system is brilliant. Unlocking characters was fun. The rest was... there was something else?! It was that forgettable and flat. The story barely exists and is at its best very thin window dressing. The interactions are nonsensical due to the random nature. The game is grindy as fuck.
I dunno. Fun once. I have zero intention of playing any more of it or any successor, ever. Done way more than enough Gloomhaven for my life.