God of War, Dark Souls, Elden, The Witcher... All of these games have a system to optimiza your character without the need to grind for hours non-stop. Armored Core will also have a complex build system for the mechas.
The problem with Diablo for me is that it is just that, just building a character that hits hard. If you have a good build, everything is waaay too easy unless you are going into dungeons 20 levels above yours. And even then, it doesn't feel rewarding because killing the enemies isn't hard, it just takes too long. Like, it was taking me 10 seconds to kill a basic minion, and even that felt better than going into a dungeon and obliterating everything.
Maybe I could enjoy building a character if I didn't need to spend hours and hours grinding to level up and to get the right items with the right affixes. The grinding is just a torture, I feel I'm wasting my time.