Pico SDK is required.
This is a Raspberry Pi PICO SDK set up that I am using on Redhat in order to learn and code the PICO.
It is a work in progress and is described in a series of blog posts at The T.A.R.D.I.S. Server project.
You may fork this as you wish. Some of the code will be from the Raspberry Pi PICO C/C++ manual. As always, use at your own risk.