Agreed, drudgery can take many forms, each different for each person. To me roadwork sucks... I count every freakin step and always have. Drudgery with a capital D. Loved pushups, hated situps. Personally I always understood and didn't mind working on the little fundamentals - knowing they would appear in almost every moment of competition. I think it was Kyrie that was quoted in a piece very recently that paraphrased went something like "fundamentals need to be mastered so that in the moment your mind can be freed for creativity or being in the flow/zone of the game". To that end (and I never saw it as clearly as his statement), I never viewed the fundamentals as drudgery per se, but as a means to an end. I didn't short cut them, I made sure each was as pure as I could. To each his own though, I'm not quibbling with labels.
That said, once at the NBA/pro level I think things are different. It's my perception that most every player is putting in the basics to stay on the roster - the stuff that happens in the practice in front of teammates and coaches, trainers, therapists. The separators are the stuff that moves a person from 10 day contract to end of the bench sub, to occasional rotation player, to solid rotation player, to starter, to all star, to where ever. When Bowen is told he's an outside jumper from being an all-star - what does he do with it? Does he consider those things drudgery? But there are obviously plenty of players who have fallen off the end of the bench not due to athleticism, but maybe because those things were drudgery. Maybe that's what we used to call persistence or tenacity - fighting through the drudgery to get where they need to be. Maybe my quibble is quantity. Maybe putting up 100 shots from that spot is every day normal, and 500 is working through a temporary bump in the road, and 1000 is developing / transitioning to another skill? And for the athlete where is the drudgery / mental discipline line - in the context of a broken shot or slump, or a night at the club calling out to you, or a series at home where a new born baby is competing with gym time.
Taking things to the Nth degree I guess, but I think when you have Larry Bird, Ray Allen putting in those 1000 shots or shooting for 2.5 hours before a game it also pushes on the younger kids to push through their own drudgery (at least the smart ones get that message). Brady spends 3 hours breaking down film after meetings, Pedroia hits off a batting T to prevent creep in his swing, etc. The great ones do it. I wonder for them if it is drudgery, love of the game, a passion or drive to be the best. I wonder just what it is, and when we can bottle it (TB12 method aside).
Back to Fulz... it sounds like he is going through a number of variables. That can be a long road ahead of him. But he has the people around him to make it happen if he is persistent. It's a lot harder for the young player who is an undrafted free agent or the like who doesn't have the resources of a number 1 draft pick. It will be interesting to watch it play out.