both
magnus carlsen or hikaru
I think both are past their prime... hence the "why" they don't want to play classical time controls. In the next 2-3 yrs look for them to be supplanted by the new guard... (who is pushing up on them fast)
Is it me? The Carlsen, Nakamura, Caruana era of Chess seemed boring. I will admit I'm biased towards past eras ... it's the way FIDE went off the rails on it's candidates cycle and the lame... World championship format for Classical chess ... it's like watching a lame Professional Tennis match... Yea they got a great serve, but everyone is soy milk.
this is to learn openings
I wouldn't try to learn openings from either of these players' games.
Both Magnus and Hikaru often like to play sub-par or unusual opening setups, just to keep their opponents off balance.
They also are extremely high level with their ideas. You'd have to be a master yourself to understand just what the heck they're doing, much of time ...
this is to learn openings