Have you ever cooked a meal by yourself for more than 20 people?

Many times. You need to plan more, but it's often but that much harder really. Just takes more time.

I played music, drank my coffee, and I dealt with it. Done.

Actually I have.
It's about organising yourself.

Between the house staff and the family the house chef cooks for more than 20 every day " All 3 meals "