I have the same issue. Changed the USB-C port with a fresh one and it worked fine after that for about a month. Just today the same issue restarted; checked with other devices, the audio jack and headphones work absolutely fine.
It may be an issue with the data cable which was suggested in another post (can’t find it anymore or I would link it). Another user took their FP5 apart and re-seated the data cable which apparently fixed the problem. I myself won’t mess with those as they are not meant to be messed with - stickers on them with (!) are quite obvious.
This is somewhat frustrating because it seems to be quite a common issue with no fix or solution provided by FP themselves.
Edit: I found the post about the data cable stuff here. Maybe this helps.