Copypasting my discord comment to here for anyone trying to use mods on android:
1. Download the Files app by Marc apps & software and grant it storage permissions.
2. Install ZArchiver (or any unzip tool) and unzip your downloaded mod.
3. Open the game at least once so its folder appears in your storage.
4. In the Files app, go to Android/data/school.game/files/. Create a folder named game, and inside that, create a folder named modifications (if it doesn't already exist).
5. Now for the tricky part: in the Files app, tap the three dots in the top corner and choose "New window".
6. Open your recent apps screen (for Samsung, it’s the bottom-left button), tap the Files app icon, and open one window in pop-up view or split screen.
7. In one window, go to Android/data/school.game/files/game/modifications. In the other, go to the folder where your mod is stored (e.g. Downloads).
8. Drag and drop the mod files into the modifications folder.
9. Reopen the game. The mod should now be active.
Images below show the end result