This app was mentioned in 15 comments, with an average of 0.93 upvotes
I think Avabel fits your bill pretty well, it's not 2D but it's online, anime style, you go and defeat monsters in multiple stages, (Sometimes the enemies are crappy because they reuse previous stages monsters and just recolor them) craft stuff, and you have many boss battles that are really similar to the battles in monster hunter.
I stopped playing it because it feels really grindy if you don't spend money but maybe you'll enjoy it.
I sideloaded Avabel Online. It works flawlessly with even the menus being controllable with a game pad which is one thing many controller compatible games that aren't on the Android TV Play Store lack.