Yeah, Godot isn't as optimized for running on Android as are other engines, there's another obstacle - dev primarily develops this game for Windows, Android build is "by the way", but he'll focus on optimizing the mobile version in the future so everyone can have a nice time playing.
Unfortunately there are many factors when it comes to Godot games being compatible with Android devices, still we'll do our best, you just have to wait patiently.
I'm sorry, but that's all I can do for you at the moment.
Cheers