It's kinda a funny chart. I don't know about negative yards of separation. Also, throwing with timing and rhythm creates separation as Wrs separate on their breaks and if the QB throws the ball before their break, the throw itself creates separation for the WR and the QB throwing to an open player.
It actually looks bad for Kyler more than the WRs even if I am not putting a whole lot of stock into it. Basically implies Kyler struggles to read the field and find open WRs.
A highlight to this is Andy Dalton vs Bryce Young. Based upon this chart, it would seem that Bryce Young throws to open players 63% of the time but his WRs don't create separation. But Andy Dalton is throwing to the same WRs who magically create more separation when he is playing QB, and he throws to open WRs 6% more often.