On my freshly installed copy of platformio, in the the zephyr framework the xiao_nrf54l15 folder was missing.
I copied the xiao_nrf54l15 folder into the zephyr framework AND edited the json mentioned above.
this is what was missing from my fix earlier.
With the folder in place:
with the folder missing:
If you’re really bored, I recorded the entire error filled process of finally getting a sample to build. It’ll be on youtube in a few hours.