Granblue seems really popular. I've always assumed it was just a generic gatcha game? Why is it so popular?
If you can get used to the UI the gameplay is actualy quite deep as much as a clasic rpgs. Also, it has a lot of events so you don't have to spend a $ on that game at all, there is also no meta team. Of course, there're top tier characters but they mean nothing if you've shitty equipements (that is A LOT important more than having characters).
You've to found the balance, choose what to grind to become imba. It's a gacha game but really generous and don't force you to have a meta team like other games. You're pretty free to make team you want since depending of the synergy of characters you can get pretty quite interesting combo. Really, that's a good turn based j-rpg if you don't have any to play atm.
You can also play either on mobile on on pc version.