We tested the APK in the link below and it worked fine on neo 2 and the PUI version is 4.1.3.
Could you please tell us what is your PUI version?
Please try restarting the device or restoring factory Settings, and then installing the test apk to see if it works.
In addition,you could change the function key by modifying the following code:
For example: Change to the Trigger button on the right controller.
private bool isDone;