Not really sure how much the "stole" Winfield and TJ. Winfield went in the first part of the 2nd round. The three teams that took safeties ahead of him in round 2 might regret the decision some at this point, but it isn't like he fell way past where he should have. He was projected as a late 1st early 2nd guy and that is where he ended up. And I am pretty sure that at the time Tampa took him he was the #1 safety left on the board.
As for TJ, tough to say how his NFL career will go and if the Bucs really got a steal. There were a lot of WR taken in the 2020 draft and I have no clue how they all fared during the season. I am sure there were some busts and also some guys who didn't play due to injury. Remains to be seen what kind of pro career he is going to have.
Maybe in the case of TJ, seeing him live played potentially served as a bit of tie breaker between him and other WR on the board at that point. But so much goes into the draft and player evaluation that it is really tough to say how big a role one game can play in the overall process. TJ certainly helped his case that day with the huge game but no team in their right mind would invest millions in a player based on one performance.