I would love to get one os these and run NetBSD it. NetBSD runs better than one might think on a system with 32 megabytes of memory and a relatively slow CPU.
RP2040 is a micro-controller and does not have an MMU. It cannot natively run any OS that relies on a MMU and that includes NetBSD. One can of course write an emulator that does and run that emulator on RP2040 and NetBSD on the emulator.
edit: Emulators, of course!
This project is an emulator that is able to run NetBSD (and Ultrix, and Linux, and potentially others)!