I can name dozens of college players who made HUGE jumps between Sophomore and Junior year. Just last year Mikal Bridges went from the Soph 6th man on Nova who averaged under 10 ppg, to a legit POY candidate as a Junior who became a top ten NBA pick averaging almost 18 ppg.
Bridges big change was his shooting technique. He shot .299 from three as a freshman, then .393 as a sophomore, then .435 as a junior... all while taking progressively more shots as he got more comfortable with his new shooting mechanics.
Most guys who make huge jumps between years, though, do it with a big jump in minutes per game, too