@howil Thanks for the photos - I don’t see anything obvious on the visible side of the board, like a tombstoned component / short / etc., but high speed issues can be much more subtle.
(I also replied here related to this issue: Librem Mini v1/v2: Feedback request for USB tuning preview build - #6 by jonathon.hall)
Re-reading the thread, you mentioned that you’ve had the device for about a year, but the problem has occurred for many months. Did these USB devices work when you first received the Mini?
If so, we may want to back up to firmware from the time you received the device and see if this could possibly be a regression. For that, if you could provide the approximate date when you received the device, I can provide specific instructions to go back to that firmware release and see if there is any difference. (PM is fine if you prefer.)