I'd be willing to bet significant money that if Magnus and Wesley play a FR match again that The Magster wins the next one. I think that was a one off result. No matter how great a champion is in anything, none of them ever win 100% of all events. Boxing & mma shouldn't count in this example because opponents in those are chosen, cherry picked like the world chess championships in the old days. I wish fide used all the data from all FR/960 events to create a rating list.
By the way, the fide rating formula for blitz is very flawed. The multiplier, the k factor it might be called, is like 40 or something crazy instead of 10. It should be far less like 5 perhaps. Because what we keep seeing is crazy jumps or drops in ratings/ranking lists based on a single event. The ratings should be an average of a bunch of tournaments, not 90-95% weight given to the most recent blitz event, just ignoring most of their previous work/results. A player can be rated 2600 in blitz and have one good event and jump to 2850! It's bizarre.
They did face each other many times in the Champions Chess Tour this year, in the six events both played Carlsen finished ahead of Nakamura every time. So S:t Louis was a bit of an outlier in Nakamura's case.
As for Carlsen standing no chance against So in Chess960, that was certainly the case in the 2019 final of the first World Championship. But as far as I recall Carlsen has won the other Chess960 events he played and that was the one where he finished second, so difficult to say if he just had a bad event that one time.
True, they did play a few times in the CCT. Good catch. From what I saw, their head-to-head record was: Carlsen 11, Nakamura 7.
I wouldn't call Hikaru's victory in the GCT an outlier, though. He is the world #2 in blitz and rapid, after all. It's kind of expected that he'll be near the top of any blitz/rapid field.
And I do think it's possible that Carlsen had a bad event against So. Though it's also possible that So is just that good at Fischer Random.
If you've seen his recent 960 game against MVL, Wesley found a brilliant opening sequence (including a piece sacrifice and an exchange sacrifice) that even Stockfish struggled to find. He seems to have found a real groove in 960 play.