I second Genshin Impact, it's a great game I've been playing for I think 3 years now. Graphics are beautiful if your phone can handle it. I've been buying the monthly card (8AUD) for a year now and I never buy crystals; I find that's an affordable way to support the developers and satisfy my need for new characters.
Unlike other free games there's no annoying popups or exclamations marks to push spending on you too so that's great.
I grew up in Asia so I'm used to gacha games, but I understand western gamers might have a problem with it. If you have a gambling addiction or FOMO then this is maybe not a good rec.
I'm 40 and I love it, I've been doing pandemic-chic for a decade now and I'm glad I'm now finally considered trendy instead of sloppy.
I'll never give up my skinny jeans tho.