FWIW: related to the M.2 card suggestion, I have tried a B-key M.2 USB adapter (with a Netgear wifi USB adapter inserted), and a B-Key M.2 SD card adapter (with an SD card inserted), in the modem / WWAN slot and neither seem to be detected by the Pocket Reform - although, I’m not sure whether I would need to manually load modules to drive things in the slot… in the case of the SD card adapter the device itself has LEDs that come on indicating that it is connected in hardware terms. Looking at the schematic I wasn’t sure how generic an interface the M.2 slot is, though, it seems to be specific to WWAN / modem (I’m waiting on that to arrive right now)
(NB I have not yet had issues with wifi myself)