Too much play? Shift linkage adjustment

I need some help fellas:
Suddenly at the 700mi mark, my 2020 has developed a ton of play in the shifter. Let me explain:
On a hard suddenly downshifts were being missed and over a few miles it just went to shit. Shift pedal seemingly not returning to position.
Staying too far down or up. Now got it in the garage and the play between 1st and 2nd is way too much.
I installed Woodcraft rearsets about 250mi ago but those two or three short rides were money. No issues.
Yes, I replaced the factory shifter pedal. But no adjustment was necessary and there was no difference in shift performance initially. Now, possibly the new Woodcraft pedal is way more stiff than factory pedal and is putting more stress on shift-linkage?
What I can't understand is the play inbetween the gears makes no sense from an outside of the bike view.
Maybe I can attach a vid of the play.
The shift shaft (top of linkage connects to) seems like it moves way too much between gears suddenly.
What should I adjust or do to inspect for issues?
The linkage is tight but the QS sensor (top of linkage)spins feely but the opposing thread nuts are tight. I have never taken a wrench to them. They are tight.
The chain is slacked out and it's time for some tension. Need to do that.
But look at this play:(attaching a video separately)