Puhlease....BO5 is as much a mental challenge as a physical, plus you get off days. Chatrier is a roofed stadium (Suzanne Lenglen next year?) and now there are night sessions at Roland Garros ( I was reading they start at 8 PM this year) so I doubt the top players will have to play back to back 5 set matches within 36 hours..
So I think the ;Danish Angel could very well win this year. He's not afraid of the top players, he relishes the challenge. What happened today against a red hot Medvedev, the game plan (planned aggression and mixing the ground game with S/V and drop shots) was sound, but his execution was sketchy. Need to clean up the net game more. Again, Holger is a sponge he is going to learn from this.
If we are waiting for physical endurance and heath credentials, Janninck Sinner and Lorenzo Mussetti would NEVER win the FO, but I doubt their fans would agree with that.