Ben Boulware at Clemson won ACC DPOY being 6’, 235 lb with a verified 4.85 in the draft process, and it’s because he was put in situations that were within his means that set him up for success.
Being in a Manny Diaz defense having multiple OL getting to the second level to block you does not put you in good situations.
Flagg, who has a lot of intangibles like Boulware does, can be a good linebacker in the right scenarios. With a good d-line and a sustainable coaching philosophy now, I expect Flagg to be successful and play to his strengths.