Sadly, there’s no way to update on mobile without having to re-download the APK every time.
But the process requires you to download the new version’s APK and install it as an update.
NOTE: Do NOT uninstall the previous version, you will lose your progress.
Also, if the update fails, try freeing some space. Android is weird and sometimes will ask for 2-4GB of free space.
Any more issues arise, ask here or in the Discord Server