Microwave Frame Crack
I can't help you with an alternative for another microwave, but we had the same problem with the Furrion microwave in our 2016 Freelander 20CB.
The reason the frame cracked was because the R/H feet of the microwave were not sitting on the floor of the cabinet. They were suspended during sloppy installation, or cabinet construction, thus putting undue stress on the frame and eventually cracking the R/H corners as you've experienced.
I removed the microwave and built up the R/H cabinet floor so the microwave would sit level when reinstalled. Still under warranty, I got a new frame.
We've never had any problems with the functioning of the Furrion microwave itself.
This is just another example of having to fix various problems due to poor manufacturing. It's fortunate that I am a handy person and can fix, and modify, problems myself instead of relying on often incompetent dealer technicians.
We really enjoy our 20CB.