I disagree that the gameplay is particularly shallow. The end game requires both mechanics and tactics. That said, the end game may or may not be _rewarding_ as it's very grindy and there's a good question (for many of these sort of games) of what you're grinding _for_. But the gameplay mechanics get deeper than what you seem to have experienced.

The gameplay really isn't shallow. If you want to be a casual and not get too much into it, it is. Otherwise, there is a lot of depth you can get into. It's just that in your first 5 hours there is not much incentive, which is fine, at that point you haven't even unlocked half of the map.

The thing with Genshin that makes the mechanics rewarding durably is a consequence of the gacha for a free to play - each account is different. So you can't just use the same tactics as other people, you have to take what you get and make it work. In the process you have to learn the combat mechanics - animation cancelling, ICD, energy recharge, character switching, geo reactions and shields, crit-rate optimization, i-frames, stamina consumption, character grouping, resistances, swirling, elemental mastery, etc...

Honestly I feel the opposite. Genshin is what BOTW should've been graphics/gameplay/art-wise. Given that I paid $60 for BOTW I feel it would be fair to pay a similar amount into Genshin's store given how much more enjoyment I got out of it.

My main two concerns with the game are that there is the "Soylent is people" aspect where if you dig deeper you realize the game is funded by a small addicted minority. And second, I shudder to think what kind of 996 sweatshop that company must be given that I don't know a single western company that achieved this level of polish (and they are already known as cruel employers).