I live in New Zealand and there are many 24/7 McDonalds in busy areas. Clicking randomly on their NZ map it’s pretty easy to find them: https://mcdonalds.co.nz/find-us/restaurants

It’s the same with Australia: https://mcdonalds.com.au/find-us/restaurants

Actually, the same for the US. It’s not hard to find 24/7 ones (you need to search for a city before they show on the map): https://www.mcdonalds.com/us/en-us/restaurant-locator.html

Are you saying that there are not many McDonalds that advertise 24/7 service, or that they advertise this but don’t actually provide it?

They have over 40k locations. Many are 24/7. They also surely churn through employees, have many part time employees, and probably get many more applicants than they hire.

The employees will be hired by the franchisees but they still use the McDonalds software.

Millions is not a surprise to me at all. Perhaps that it’s tens of millions is a little surprising, but it still seems within the realm of possibility.