The only other gacha game with 3D models and environments is Genshin Impact, but it's more an open world (ubisoft style)/Breath of the Wild action beat em up. I would not recommend playing it for the story, as the tidbits of story are stretched out across a long grind, and not very well presented. It also feels very jarring to be adventuring with characters in cutscenes, but you can't play as them during gameplay because you haven't drawn them yet. Play it only if the gameplay interests you.
If you're okay with 2D, visual novel esque gacha games, then I would recommend Granblue Fantasy. This is the most friendly gacha game I've ever seen. They throw dozens and dozens of characters at you for free during the Christmas, March anniversary, and Summer events. I have 265 characters and I've never dropped a dime on the game, nor have I grinded for characters. I only log in to do the next chapter of the story when I feel like it, and only log in during the events to get my free characters. The story mode is really easy so you can just pick your favorite characters and go with them. You can't get more casual than this. They also don't show you advertisements, and don't wave the cash shop in your face.
(That being said, SAVE YOUR CRYSTALS! Save them up so after the events finish, if you have a character you REALLY WANT but your were unlucky and didn't get it from the free rolls, you can draw 300 times to spark that character).
The art is by Final Fantasy veteran Akihiko Yoshida, and the music is by Uematsu and Narita. The gameplay is basic 2D mobile visual novel stuff, but it works.
The game has an official English translation.
The first story arc is basic fantasy stuff, but the characters are charming enough. They got a different writer for the second story arc, which I hear is better, but I haven't gotten that far. Some of the side stories are pretty fun (like the 4 Dragon Knights storyline).
You just need to be using either Google Chrome or the Safari browser.
- Click the "Set Language" drop down and select English
- Click "New Game
- Play through the tutorial
- Create a Mobage account. Chrome automatically translates the page for you so it should be easy, standard account creation process. Sign in Granblue with the account and you're in.