There are any number of stats that will show Justin Jefferson had the best first four years of any wide receiver in NFL history. By any standard, the guy is a ridiculously good player.
There is also the basic understanding that defenses must game plan against specifically Jefferson, thus making him advantageously impactful for the Minnesota offense even when the ball isn’t coming his way.
With a new quarterback, J.J. McCarthy, on a rookie deal and entering a season where Las Vegas oddsmakers think the Vikings will finish last in the NFC North, signing Jefferson to a four-year, $140 million contract ($110 million guaranteed) made plenty of sense.