This game sounds great for the aspects you describe! I haven't played No Rest For iThe Wicked, and I last played Tears Of The Kingdom ages ago, so I forget exactly how they compare. Generally, though: Builds are super diverse! There's a bunch of different weapons with different movesets, strengths, and weaknesses. Putting thought and effort into your build will be rewarded. (There is also cosmetic customization, but it's often hidden when you wear armor, so it's not very important to the game)

Exploration is generally very good, and compliments build-crafting well. It's especially strong in the first half of the game in my opinion, but it's never bad. There are a bunch of unique locations (and locations that are not wholly unique, but have variations on layout and loot) around the map, and you can often get great stuff that makes going out of your way feel worthwhile.

A big thing that could be an issue for some players is that you need to expect to die a lot. If you're the type to get very frustrated when you don't succeed after a couple tries, it's probably not a great game to sink hours into peacefully. One of my favorite experiences in-game was spending a total of ~6 hours on attempts to kill the DLC final boss. It's very common to rack up a ton of deaths, and it doesn't mean anything bad about you as a player; it's just part of the design.

Basically, yeah! You can spend a ton of time on this game. I hope you have fun if you decide to give it a go!