His long speed isn't questionable, though. His 100M PR is right there with the top Dade backs of this era and his film shows multiple, long TD runs against elite teams.
You list him at 5'10, 173, but he actually measured 5'10, 180 last year. For comparison, Knighton was 5'9, 173 at the same event.
Now, I don't put too much into sophomore testing. Almost all of the top 2020 prospects tested terribly last year. They were young and growing. Unfortunately, Parrish got a minor injury in track and couldn't re-test this year. So I suspect the old stereotypes will continue. But I'm not going to sit and worry about his shuttle when the film shows that he has the best moves of any back in Florida.
My issue is the perception of Parrish as something below the other guys. I would dispute that based on seeing him live. The other guys are elite, and he is elite, too. To quote Bill Parcells, running back is a production position. His production against elite competition speaks for itself.