It’s just one of the best crafted games ever imo.
In addition to being able to upgrade any weapon, you can also attach special abilities to them (this one let's me do a charge! That one makes me flip over attacks and slam my sword! The other one let's me make a magical flame!).
So in the end, while the base system is less complicated than breath of the wild's combat, the customization makes it "wider."
Don't let cries of "it's difficult!" enter into your judgment. Every enemy, especially bosses, are just Megaman battles where you memorize patterns. Due to the rpg elements and how you customize your character, you can ignore entire boss mechanics all the way to the end if you so choose. The difficulty people complain about likely comes from your lack of movement (compared to spiritual ancestor ninja gaiden black) and the fact that there is a noticeable delay between commands and execution coupled with a command queue: if you press dodge you will note your character is not immediately dodging so you press it again: your character then dodges twice.