Folks don't realize or remember that quality WR's MAKE plays.
Sure sometimes the ball isn't perfect. In fact, for most QB's, passes over 30 yards in the air are RARELY perfect. Usually they require the WR to track the ball and adjust their speed to field it.
We watch guys like Jayden Reed get wide open and slow down or speed up or run under the ball EVERY WEEK. We aren't talking about superstars (although Reed is quite good), just good NFL players.
Mack is not a good NFL WR. That doesn't mean he can't block or catch a perfect missile in his chest on a slant. Of course he can. But he can't MAKE a play happen.
All the WR's that make tough catches or explosives are part of the reason those plays are successful. Mack is in year 7, he doesn't have that ability and never will. This isn't Madden where you press X to catch.