https://github.com/kamisori-daijin/pico-rv64-emuI have successfully run a 64-bit version of xv6-riscv—which includes an MMU—on the Raspberry Pi Pico 2W.
No PSRAM is attached.
I built a software emulator and ran it on the Hazard3 core.
(It should likely also run on the Cortex core.)