I listen to Chris Simms regularly because his understanding of the game goes way beyond most fans...he's really good at watching the film and letting you know what's really happening and I learn quite a lot. A line he always throws out there when talking about DK is "damn, sometimes I wondered if their coaching staff was trying to lose the game. It's like they don't know DK Metcalf and AJ Brown are their best players." He also takes issue with their QB from the tape.
I've seen Yolo here on The Wall talk about how you have to be careful with production with college wide receivers because it's a dependent position- the system, playcalls, quarterback and O-line need to do their job for WRs to have a chance. It might be the most dependent position and therefore is the position most requiring CONTEXT in an evaluation rather than just statsheet scouting. It really takes grinding the tape (which I myself do not do) to get a true picture.
Lastly, we might want to keep in mind that DK was 20 years old this season. Awhile back someone posted comparisons of DK's production at age 19 and 20 compared to Julio Jones (I think he was included), along with other WRs, at that same young age...and lo and behold, in this context Metcalf's production actually stacked right up. A lot of college players are a good deal older than that, for example Robert Foster is a year out and turns 25 in 2 weeks.
With his size and not only speed but crazy acceleration, along with nuanced technique to beat press, he can be a nightmare for CBs. The Bills don't have anyone like that. And not every WR wins the same way...Mike Evans doesn't have to run whip routes and triple breaks. Neither does DK