My DH has repaired mine twice. Once was when the turntable motor quit working. He does know his way around electricity and wiring. He looked up on Youtube to see how to access it and ordered the part off line, then put it in. Did not have to remove the microwave. Another time the door latch broke, so no using it until that was fixed. Again, he ordered the part off line then looked up a youtube video on changing it.
I am glad he is so handy with all things in the motorhome. I do agree, if you are inexperienced in this, better not try it. But I would think an appliance repair person would give it a shot. Both times, the parts were quite cheap. The motor about $13 and the door latch $4. Still using the 14 year old micro/convection.
Years ago, we had a first generation microwave that quit working. It was a countertop model and we took it in to an appliance repair shop and they fixed it. That was much cheaper than buying new because back then, even the basic ones were several hundred dollars.
So if you are stationery and not on the road, you might check small appliance repair shops. You could even order your own part and see if someone would install it. Worth a shot.
Dale