I thought it was of less importance, but I see now, that it of course is very important. I run everything through a Caldigit Thunderbolt Station 2 (or 3). Not the newest one. It works like a charm….the Kemper RM, my external monitor, midi devices, RME Babyface Pro fs, my external SSD and so forth. Cable is still 10 years old at least.
Have you tried on a different Mac and on a pc? Mine is working on pc and my Mac with the latest Ventura and the previous Monterey. No issues at all.
If it doesn’t work on other devices at all, I would think that it would have to be the Kemper. But if it works on other Macs and pc’s, I would think that it would be the Mac (settings of some sort). When I was installing my RME Babyface Pro fs, it was a pain in the butt. I had to go deep into the Mac’s safety settings and turn off the safety settings, that don’t allow certain non-accepted apps to be installed. It’s a M1 thing and they all have to do this. I don’t know if that is something, you would need to do. I wouldn’t think so 🤔
If your Kemper doesn’t connect to ANY computer, I would open a support ticket at Kemper again and ask, if it is possible to let their people handle it. It’s in Germany though. I don’t know where, you’re located. I just know that my Kemper has traveled to Germany and back to get new LEDs/screen. It took 8 days or so from Denmark from when I sent it till I had it in my possession again. Very fast and reliable. I love the Kemper company. I would think that they would help you out. I don’t know what you have been corresponding with them though and why a suggestion hasn’t been brought up.