Would that open the game up to modding? Because I really want to play this game with koikatsu models.
While they are both Unity games, with similar file structures, you would need to be quite the modder to import models from another game.
And get them to work as intended.
The game is technically already open to modding, if you know how to manipulate the assets.
I've created higher resolution textures in the past for Rabbit Burn, but they suffer from weird seams because I'm not using the original texture editor.
If you knew how to use blender, you can technically edit the meshes, but that's out of my skill set.