Make sure you have between 400 and 600 lbs of hitch weight for that TT.
Shortening the ball mount (to reduce rear overhang distance) can help a bit.
Make sure tires are aired up to max cold sidewall pressure. If P tires, switching to LT tires (stiffer sidewalls) with a lower profile could reduce side to side tire squirm.
The sway bar can help, but if it gets wet in rain the friction is reduced. And when backing up it must be loosened or it can get bent. I prefer a WD hitch with sway control built in, like for example Equal-i-zer or Andersen No-Sway.