Gonna have to disagree.
Johnson averaged 17.7 per catch in a year that Allen averaged 6.7 per attempt with a 56.3% completion percentage (2017 - both player's last with the Wyoming program).
For reference, Jordan Westerkamp, Kenny Bell, JD Spielman, and Stanley Morgan played a combined 15 seasons at Nebraska and had a total of 1 (one) season with a per catch average of greater than 17.7 (JD Spielman at 18.3 in 2019).
For further reference, Taylor Martinez, Tommy Armstrong, Tanner Lee, and Adrian Martinez have a combined 1 (one) season at Nebraska with a YPComp. lower than Allen's 6.7 in 2017 (TMagic at 6.1 in 2013), and the only QB at Nebraska to post a completion percentage lower than Allen's 56.3% in 2017 was Tommy Armstrong (who did so in all four of his seasons).
I'm not saying CJ Johnson is an All-American if he attended NU or that Allen was a scrub (he was great in 2016 and he's certainly developed into a terrific pro), but Johnson did as much for Allen as Allen did for Johnson and the QBs at Nebraska have had, generally, better seasons than Allen did in 2017 with the exception of the ever so important TD/INT ratio. I doubt there's a direct carryover of statistics from G5 to P5, but to say Allen carried Johnson is not accurate.