Ballet is probably uncommon among skaters, but I’m guessing. However, balance requires core strength which can be developed by workouts in the gym. Gym work is arguably as important as on ice training. I know a young skater, she’s 19, who has been skating a couple of years and she recently won an amateur competition for skating jumps at our local rink. She skates maybe 8 or more hours a weeks, and does several hours a week at the gym. She also has a coach, an ex olympian, and I think a coach is essential to get good technique. I suspect she will never get to national level, but she might become a very good skater. I’m guessing of course.To be really good, start young, as said earlier.
However, late starters can become good skaters, and more importantly, it’s great fun. (Maybe the fun goes for serious training?)