Here is where I land on 6th and 7th rounders. If I am going to give credit to GMs for UDFAs, I am going to point out 6th and 7th rounders who they do not get meaningful contributions from.
KeeSean Johnson. 585 offensive snaps and 11 special teams snaps over two years. Call it whatever you want I guess, but it sure isn't a hit.
Maybe not a hit, but I don't think it's a miss for a 6th round WR.
Here are the ones from 2019:
Career Receptions / Yards / TDs
Keesean Johson (AZ): 36/360/1
Travis Fulgham (3 Teams): 38/539/4
Juwann Winfree (2 Teams): 0/0/0
Marcus Green (2 Teams, now CFL): 0/0/0
Kelvin Harmon (WAS): 30/365/0
Scotty Miller (TB): 46/701/4
And some more from 2018 (with another year of counting stats of course:
Damion Ratley (4 teams): 29/407/1
Deon Cain (3 teams): 9/124/0
Ray-Ray McCloud (3 teams): 25/113/0
Dylan Cantrell (4 teams): 0/0/0
Russell Gage (ATL): 127/1,295/5
Equanimeous St. Brown (GB): 28/445/1
Cedrick Wilson Jr (DAL): 22/235/2
Braxton Berrios (2 Teams): 43/509/3
I find it interesting that of the 14 only 5 remained on their team more than 2 years. The only major 'hit' seems to be Russell Gage (and maybe Scotty Miller?). Granted, I'm not taking ST into account because I don't follow ST depth charts of other teams.
Essentially, KeeSean gave us about what we could expect from a 6th round WR and has better #s than all but a few. To expect anything more from a 6th rounder just isn't realistic IMO.
(Sorry if this formatting is bad - still learning the site)