I have a friend with a large extended family. Many of them share a long complicated surname that always gets convoluted. Other relatives have a different last name completely. They get together a lot and different people make restaurant reservations. They just always reserve under the same easy name. I can't remember exactly but it's something like Brown. Everyone knows to just ask for that table when the arrive. Seems logical to me.

Hotels? I know they have a way when working with celebrities who often either on a different name.

I have one friend who's a partner in a family company. She used her married name personally, but her family name professionally. I'd guess she books hotels under the legal name, I'll have to ask. I actually know a number of people who's names have changed through marriage/divorce, etc. Pretty much all of them still continue to use the name the profession knows them by. But again, in those cases you can easily book under the name that's on your ID.