I’ll wade in and make one comment as there are some younger posters, who may not be aware of the history of it.
Im pushing 60, and back in day it was commonly accepted that Black college QBs lacked the intellectual ability to handle the intricacies of an NFL offense and were best suited to play WR/RB. There were still NFL personnel who wanted Lamar Jackson not as a QB, but at other positions. IIRC, there was concern regarding his Wunderlic Score.
This Wikipedia page provides a good summarization from various sources IMO, for anyone interested in the subject.
en.wikipedia.org