Google Play shows "Your device isn't compatible with this version" when your device does not meet the app's requirements.
iReal Pro for Android requires Android 10 or later. On anything older the app cannot be installed, and no amount of troubleshooting will change that. Check under Settings > About phone > Android version.
If your device does run Android 10 or later and you still see the message, the Play Store itself is at fault rather than the device:
  1. Open Settings > Apps > Google Play Store.
  2. Tap Storage, then Clear cache.
  3. Restart the device and try the install again.