I've created a Github template for anyone who wants to create a usb midi controller using the Raspberry Pi #Pico. Just click use template and off you go making your own custom midi controllers.
https://github.com/madskjeldgaard/raspberry-pi-pico-usbmidi-platformio-template/tree/main
GitHub - madskjeldgaard/raspberry-pi-pico-usbmidi-platformio-template: Make a usb midi controller with a Pico board and the Arduino framework in Platformio
Make a usb midi controller with a Pico board and the Arduino framework in Platformio - GitHub - madskjeldgaard/raspberry-pi-pico-usbmidi-platformio-template: Make a usb midi controller with a Pico ...GitHub