Most restaurants use microwaves. They may not use it to prepare the entire dish (that’s reserved for mass-market faux-nice places like Red Lobster), but it’s a standard piece of commercial kitchen equipment. Reheating frozen soups, for example, usually starts with a quick zap to get the process going.

Please don't speak authoritatively about things of which you are ignorant.

Almost every restaurant uses microwaves for some part of food prep. Go work in a kitchen for a bit.

You'd be surprised of what I'm cognizant.

If "almost every restaurant microwaves" in one's area, they should probably move to a better area.

Though I'm not sure what you call a restaurant. Does it include fast food "restaurants" for example? Or some 2x-3x the local price tourist trap in places like Barcelona, Rome, Amsterdam, Paris (say, Montmartre) or the Greek isles?

Indeed, the vast majority of restaurants are filthy, terrible over priced eateries where you are gambling your health. Especially after covid.

How much would you like to bet on sone Michelin starred restaurants having microwaves in use?