I like this idea, it's cute. Especially how it's a 3D object, you can go even further with that and make the buttons a physical object you need to push, have "beeping" sounds coming from an AudioStreamPlayer3D from a little speaker on it, having you need to open the back to replace the battery occasionally, stuff like that. A real Tamagochi simulator! Also, as it's 2022 there's so much you can do with logic and programming that simply wasn't feasible in those tiny computers, beyond just picking up poop and feeding them.
Heck, you could even throw in evolutionary algorithms in there with genes and all, could be an interesting title. It just needs to be in a format where it's easily available, like a home screen widget for the phone or a webapp, so people can check in on it occasionally instead of dedicating their entire focus to the game.