I think the challenging aspects of the Souls games are demonstrably learnable, generally follow a certain internal and external logic that is understandable and quite predictive, and rewards the player when they apply each lesson learned into that one successful run.
Sports games have always scaled their difficulty in a way that often feels insanely robotic after a certain point, especially at the highest ones (IMO). In fact, I kind of disagree with your thread's versus logic at a fundamental level because, outside of NG+, Souls games have a finely tuned and fixed difficulty and sports games don't/can't due to the real-life variables they attempt to emulate (the sudden on-a-roll adrenaline rushes of a star player, wind speed in a golf game, formation changes, whatever.) It's like comparing a yo-yo to swing ball; one is far more predictable.
I will choose a different language than yours and say that the A.I. of some sports games at high difficulties is often far less predictive and arguably designed to be unfair rather than challenging. There's nothing "brave" about me saying that, though, because it's a by-product of its genre, not an arbitrary assignation of being "more difficult" than a famously challenging game like, say, DS1.
The frenzied boss/enemy states in DS3 and BB specifically, however, have some of that unpredictable behaviour, though still incomparable. Just my opinion, I'd love to be corrected if I've totally missed something or edged close to an ignorant viewpoint.