!!! I'm not a programmer and this is just my personal code shared with you, so don't expect a clean or ressource saving code :)
I love my G27-Racing-Wheel and needed more buttons, so I've extended it with two rotary buttons.
For my Project I'm using two ky-040 Rotary Encoders as inputs, a ESP32 and a 3D-Printed Plate for the G27.
Bluetooth Gamepad: https://github.com/lemmingDev/ESP32-BLE-Gamepad
Rotary-Encoder: https://github.com/buxtronix/arduino/tree/master/libraries/Rotary
Buttons: https://github.com/evert-arias/EasyButton
You will find the 3D-Model on Thingsiverse: https://www.thingiverse.com/thing:4246428
Connect the + with 5V (VIN-Pin)
Connect the - wiht GND
Connect the CLK, DT, and SW Buttons as defined in the code
