Most combine trainers think they can shave .1-.2 seconds off a 40 time by improving technique and training for explosiveness between the end of the season and the combine.

Waller is a great football player but speed was clearly his weakness during his playing time here, just go back and watch the Miami game to see it on full display. He also went pro early if you want to count 2020 as a redshirt where he only played in a game and a half.

If he fully bought in then you'd expect him to get at least a tenth faster, so either he's naturally a 4.8 guy, or he wasn't fully committed. Sure he may be a Josh Norma who just isn't that athletic but a great player, but even Norman made Waller look slow.