Unlike many modern Android games that use a generic folder on your SD card, Mega Man X DiVE Offline typically installs its core assets in the protected system partition. However, the save data location depends on your Android version and whether your device is rooted.
Recommendation: Even if you don’t edit, backup your save every 10 hours of play. One corrupted update or accidental uninstall can erase everything permanently. mega man x dive offline save data android
For a complete walkthrough on expanding your offline game with mods (specifically for the PC version or compatible emulators): Go to Settings > System > Backup
You do not need to root your phone to save your progress, but you do need a PC or a third-party file manager that bypasses the "Android/Data" restriction. How to backup your progress (No Root required)
adb exec-out run-as com.capcom.rxdoffline cat files/user_0.db > user_0.db