Hi, I found this card that works but not out of the box: LWB5+ M.2 SDIO, see https://forums.puri.sm/t/using-an-alternative-wifi-card-lwb5/
The issue with that one is that power saving depends on an external oscillator which the Librem5 does not have. Finding a wifi card with an integrated oscillator would be better
edit: sorry I just realized your issue was about using the USB interface instead of SDIO, and not about finding a wifi card