Damn, that’s a far cry from my experience with MX mice honestly. I’ve had my MX 2 from release and nothing like you’ve described happened to the coating on mine. I know some of that’s likely down to body chemistry, I have fairly dry hands and I keep my periferals religiously clean so perhaps I’m not the best example of an average end user.
As for breakage, again, nothing of the sort. My brother has a master 2s and my brother in law has the master 3 and neither of them have had any breakage except that I had to swap a puffy battery on my brothers one about 4 years in which isn’t unusual for lipos and liions that are kept at full charge for extended periods of time.
Again, not questioning your experience at all, we all have different situations that we use them in and I don’t know what yours is, but just wanted to share my personal experience.
I use some electronic safe foaming cleaner I get from work and that does the trick. For any detailed stuff like the scroll wheel I’ll use a toothpick or sewing needle to get into the grooves. I never spray the cleaning foam directly on the mouse, just apply it through lint free cloth. That seems to do the trick for me! I also picked up a carry case for when I’m transporting mine.