Years ago the game was less than 2 GBytes in size, then RenPy could make an .APK file. Now game is 12 GBytes, and Android does not support .APK files larger than 2 GBytes.
Why combine Windows and Android version instead of just leaving an Android-PacKage file?
It is not a combination, there is no .APK file anymore. Read the instructions above on this page under the heading “How to play on Android”. Game on Android works under emulator that allows running the PC version in Android.