Adding to cima2u-net, you should use
adb logcat to retrieve the logs from the Android session, which should include detail about the Godot game.
There will be a lot of content in the
logcat output, but you can search for
godot and for your application identifier to find relevant logs. You can use
adb logcat from the command line or (I believe) through Android Studio.
Make sure to export a "Debug" build to have relevant information. You can also enable "Debug > Settings > Verbose Stdout" in the Project Settings to have more information printed by the Godot process while it runs.
If there's an actual crash (e.g. a segmentation fault, with a backtrace involving Godot code), you can build your own
debug template for Godot to have all debug symbols (the official debug templates use the
release_debug target which has debug information but some symbols are stripped). See Compiling for Android.