Jazz great John Coltrane had such facility on his instrument and such advanced harmonic thinking that Lee Konitz, one of his contemporaries, suggested Trane practiced 10 hours a day.
Bassist/composer Charles Mingus took his practice a different way. As he progressed he spent less of his practice time actually playing his instrument and more time listening to others play. His reasoning was that physical practice existed mostly to a) build up his stamina, b) improve his facility and speed, and c) increase his muscle memory. Writers may not spend more than a few hours actually putting stuff down on paper or disk, but the best ones read everything in sight.
Your practice should include time when you’re actually doing your work, and immersion time studying the work of artists you admire. Both count as practice; the trick is to find your ratio and to be consistent about it.