For some historical context, I looked at the top receiving tight ends last year. There are a LOT of examples of guys who had pretty bad rookie years, but last year were very solid to excellent tight ends (at least the receiving half of the equation anyway). Disclaimer: This is NOT a prediction of who Keene or Asiasi will become, because as we all know there are tons of examples that go the other way too. But just for some context.
Darren Waller - First three years he played a total of 14 games and 16 catches. Last two years? 197 catches for over 2300 yards.
Logan Thomas - First four seasons he bounced around (injury year too I believe) before breaking out with Washington last year for 72 and 670.
Jared Cook - Rookie year he played 14 games and had 15 targets for 9 catches, 74 yards, 0 TDs. He then became a guy that people are pissed we didn't sign to replace Gronk.
Darren Schultz - 17 targets for 12 catches his rookie year. The next year he played all 16 games and had ONE catch. His third year in 2020? 63 catches, 600+ yards.
Robert Tonyan - 14 catches combined between his first two seasons in 27 games. Last year 52 for 586 and 11 TD's.
Tyler Higbee - 11 catches his rookie year, and then didn't break 300 yards receiving either of the next two. The two after that he's averaged 600 yards per season.
There are guys who jump in right away and get it. There are guys who don't and never will. But there are also enough examples of guys that look pretty useless early in their career, then either something clicks for them or they find themselves with the right combination of QB, coach, scheme, supporting cast, or some luck, and become productive players. Pointing out that one weird rookie season doesn't damn a player to mediocrity for eternity is a take that shouldn't be controversial.