I think endurance sports (and many other sports, like rock climbing, which I enjoy), are a mix of type 1 and type 2 fun (https://www.rei.com/blog/climb/fun-scale). There may be some suffering while you do it, but the overall experience is positive when you look back at it. This is quite different from surgery without anesthesia, which would definitely not be fun in the end, at least for most people.
It wouldn’t be fun, no, but it would sure as hell make you appreciate not undergoing surgery without anaesthesia.
From a personal perspective, I spent years suffering from a mystery illness (ah, the joys of tropical diseases), and it made me appreciate the times when I wasn’t having an acute episode immensely, which otherwise would have been “ordinary”. My wife would be like “there are leaves all over the driveway!” and I would be like “yes, aren’t they beautiful?”.
