I strongly recommend the port from Earle F. Philhower:
- It relies on the official Raspberry Pi Pico SDK, and not the cumbersome mbedOS the Arduino port is based upon;
- It provides macros for the GPIOs, as well as for the neopixel and the three RGB LEDs;
- It can easily be debugged with SWD, for example the very affordable Segger Edu Mini and its excellent Ozone GUI, or a Raspberry Pi Pico turned into a programmer-debugger PicoProbe.