Anecdotal facts:
I started in the 84h group in 2019 and did PBP “the normal way”, with rather minimalistic sleep.
Between Mortagne and Dreux on the way back I was overtaken by five guys from the Alberta Randonneurs. They had also started in the 84h group but were going strong and very fast, almost at the end of the event. I was really wondering what was going on.
Later I found out (by hearsay) that they were known for not liking to ride in the dark. Instead they apparently had two evenings with nice dinners and two full nights of sleep. In the end they were a bit faster than I (but probably also a bit stronger overall, and a very well functioning group of a good size). Tactics can be very different!
Maybe one of them reads this and can confirm or correct the rumors ;-)