There is no magic RV microwave that I am aware of....kind of like RV toilet paper. Yes Dometic makes one that puts up with more vibration, but other than that, not a heck of a lot of difference that I know of....
https://www.remodelyourrv.com/rv-mic...he-difference/
https://crowsurvival.com/can-you-use...wave-in-an-rv/
I promise you, the Samsung microwave that the factory put into my rig was not a designated RV microwave. I am going on year 18 with it and only twitch/tick on odd number days due to the heavy exposure to escaping non-RV microwave energy. I've reduced the risk by wearing an hat made of alum foil.
In all seriousness though, find one from a reputable manufac that fits the location and you should be fine. The factory did place sufficient venting to accommodate a size per size swap.