Torque Converter problems?

I've been trying for over a year to diagnose something wrong with the truck. I have a 2012 tacoma Prerunner with the 1GR and A750. I've eliminated drive shaft as a possible cause. The problem feels like a bad shift that makes the cab jump or that the transmission is struggling to get the right gear at the right time. It has been flushed twice now by a trusted shop, and the only time I saw any improvement was when I added 2 ounces of lubeguard shudder fix. That worked miracles for a day or so now it just seems to be a little worse.

In combination with this there is a loud rattling noise when I accelerate like marbles in a can, I doubt it is catalytic converters cause I would get a code right?

One thing to know is that the truck was at redline off the limiter for a good 3 minutes when the secondary air pump gave out on me on the highway on ramp a couple years ago. got that recall done. but since then the truck hasnt felt the same. looking for any help I can get, losing my mind trying to figure this out.