i have the board with a ryzen 5600x in operation. it was really a pain. no error message no nothing. just black screen. luckily my colleague had an older ryzen at hand...
For our future fellow sufferers: AMD offers loaner CPUs for BIOS updates (Google: "AMD Bootkit Zen 3").
AMD describes the procedure on their website, there are some bureaucratic hurdles, but I had the CPU within a week.
Unfortunately, Digitec support was absolutely helpless here, so you're just wasting your time.