I'm sure several good Sox players, especially at ages 19 (YRod) 21 Phillips (no farm games, yet) and 23 (Holobetz) were not top 30, at some point in their farm careers.
Abreu was ranked 29th, Dobbins began at #24, DHam was 30th and lower, once and gave us a huge fWAR season in 2024. Elmer Rod was 25th and traded for Narvaez.
Rafaela was in the Sox system for several years (since 2018) before jumping to #19 in APR '22.
Crawford was below 30 and then 23rd in summer '22.
Wong was 18th to 20th in '21. Bello was below 30th and 19th in 2020. Duran was 15th and lower, at times.
Hell, Devers was 18th and lower. We got Betts in 2011 and he debuted at #10. Vazquez started pretty low. JBJ was 19th and lower, at times. I could find more.