I'll give a very honest review for this game according to my personal experience.
Genshin's combat mechanics rely heavily on elemental reactions. They don't have the classic dodge/parry/counter mechanics like most combat games, so it's kinda inflexible, but relatively easier. Some characters have their own unique gameplay.
World visuals are beautiful, some exploration abilities are locked behind specific characters, but there are exploration mechanics in the later regions.
Music? 10/10. Hoyo's music in general are top notches.
For the story I'll give 6.5/10, the concepts are good but oftentimes they're poorly excecuted, often includes too many excessive dialogues and unnecessary banters that aren't really relevant. Visual storytelling also 6/10, they have good pre-cutscenes in the beginnings but lately they either use black screens or recycled animations, it's only slightly improved in the latest Natlan update and Nod-Krai update. Slightly. And there's no dialogue skip button in this game, so you'll have to sit through the whole story dialogue scenes whether you like it or not.
MC is neutral, no personality that makes them stand out. They barely even talk. They have a flying travel companion that literally comes out of nowhere (no background, no origin, no idea what she is or where does she came from) that couldn't keep her mouth shut for a minute. Story revolves less around the MC and lean more towards the world they're in. Typical gacha MC that's widely liked by the characters, praised and welcomed everywhere for the sake of it.
For the lore, I'm not a really lore enthusiast so I can't give reviews on that. The lore is deep, no doubt, but whether it's well-constructed or not, I can't tell.
In-game rewards are sometimes generous, other times they could've given more.
Limited event minigames are fun and visually attractive, the gameplays are decent
My main problem with this game is the lack of QoLs features. No resin (energy) overflow, no dialogue skip button, no shield indicator bar. It's ridiculous because Hoyo's other games that were released after Genshin has all of those, there's no reason for them not to implement those features after nearly 6 years.