Strangely enough, the build on comment #104 works just fine for me on my Odin Pro (albeit crashing trying to set permissions, but doing it manually makes it work), and a friend of mine who directed me to this thread that has a phone where he had the black screen on official builds has said that it works perfectly on his end, allowing him to finally play Mania on mobile.
As a request, once you get these ironed out, could you see about making apks for Sonic 1 and 2 (and maybe CD)? I like how you've made the APK show the game instead of the engine and given the option to change the filepath, and since Sonic 1 and 2 use the same RSDK engine, you can't really have them both on the same device without making one a mod or cloning the engine decomp.
As a request, once you get these ironed out, could you see about making apks for Sonic 1 and 2 (and maybe CD)? I like how you've made the APK show the game instead of the engine and given the option to change the filepath, and since Sonic 1 and 2 use the same RSDK engine, you can't really have them both on the same device without making one a mod or cloning the engine decomp.