The actual Forza Horizon 4 game on PC and Xbox requires over 70GB of storage space. Even with extreme compression techniques, the assets (textures, 3D models, audio files) cannot be compressed down to the "50MB" or "500MB" files often advertised on shady websites. A game of this visual magnitude requires gigabytes of data. If you see a link claiming to be Forza Horizon 4 that is only a few hundred megabytes, it is almost certainly a fake.
If you already have the game installed on a powerful home PC, you can use the Steam Link App to stream the gameplay from your PC to your Android device over a local network. forza horizon 4 highly compressed for android
Here is the technical breakdown of why a "Highly Compressed Android APK" of Forza Horizon 4 is generally a myth or a misrepresentation: The actual Forza Horizon 4 game on PC