Bluetooth HID Profile Tester
Test if you have support for Bluetooth HID Profiles on your Android 9 or higher device.

Play Store Link: Bluetooth HID Profile Tester

Turn on Bluetooth and test if your Android 9 or greater device has support for Bluetooth HID Profiles.

The following image will be seen on your device if the test is successful:

A successful test is usually quick.

The following image will be seen on your device if the test fails:

A failed test usually takes longer to finish.

If the Tester app fails?

If the tester app fails, it means your device firmware does not have Bluetooth HID Profiles enabled or implemented, and is unable to function as a gamepad controller or other Human Interface Devices.

You can still try to enable Bluetooth HID Profiles if your Android device is rooted with Magisk and is ≥ Android 9 with a Magisk module.

In Magisk, install blefinal.zip from GitHub Here

Reboot after installing and retry the Tester app!

If that fails, try the old version:
In Magisk, install magisk-bluetoothhidenabler-v2.zip from GitHub here
Reboot after installing and retry the Tester app!

Alternatively, you can just use root to manually edit the required files in your device. Check this video for how to do that. The Magisk module would of course be easier than this though.