Going 52 weeks falls just right for Nadal on this. On Hardcourts it starts him in Canada where he won the title and then the US Open facing Medvedev both times. He avoided all the big threats as usual on the way to both trophies. Nadal quit in Paris to avoid Djokovic, lost to Zverev WTF RR and got eliminated later avoiding all major threats again (No Djokovic, Federer, or Thiem). DC where there was nothing but mugs on the menu from start to finish. How often does Nadal play 11 indoor HC matches avoiding the other 3 top players in the world? Finally meets Djokovic and Thiem once each in 2020 with both being decisive affairs really. Didn't have to do much to lose. Everyone else he played in 2020 sucked except Kyrgios who can't return (this is a serve related stat thread) and Goffin who put him away in straights. It boils down to Nadal avoiding top competition, making short work of weak mug players, and going down quickly in losses against top comp.
Federer suffers because it takes away 2 of his best results that occurred at that time being Dubai and IW. Federer wasn't the same after Wimbledon and bombed in Cincy. A place he normally does really well. The US Open started slow for him and then the 5 setter with Dimitrov to end the misery. He peaked for Basel and the one WTF RR vs Djokovic and that was it for 2019. 2020 he's played 2 tough 5 setters and a 4 setter where he was fighting to survive. Long matches means losing serve and a suffering 2nd serve. He struggled against players he normally wouldn't and had injuries to boot.
Long story short, the cherry picked 52 week period favors Nadal because it rewards him with every tournament on his fav surface clay. That gives him the automatic advantage in the all surfaces/HC categories because Federer loses 2 of his best HC tournies and he struggled after Wimbledon as did Djokovic. Nadal sailed through the next few weeks like nothing. Basically a mouse with both cats away.