Bruh, Cooks got his yards playing with Brees, Brady and Goff (in McVay's system). Diggs played with Teddy Bridgewater, Sam Bradford, Case Keenum, and Kirk Cousins.
First, never call me bruh.
Second, your point fails to address the simple fact Cooks has accomplished more. You can say it is all because of the QBs he has played for, but it doesn’t change the fact that he accomplished a lot. He has also been traded for a first round pick twice in his young career. So clearly GMs think pretty highly of him too.
2015 - he was the leading receiver on NO with 300 more yards than any other player
2016 - leading receiever, ahead of Thomas
2017 - second only to Gronk and he had only 2 fewer yards
2018 - second to Woods by 15 yards with 1,200 yards of his own
The fact he only returned a second rounder this time is likely because of his down year and injury. Again, none of that changes the fact he is more accomplished. You're talking about how he projects going forward, not what he has accomplished.
Come on folks, we can be Bills fans and be objective.