Even though this full sized SUV is derived from a F150....the SUV market folks demand even higher levels of ‘ride quality’...typical for all badges...so the OEM normally softens the springs (changes the force rates over travel) and other ‘car’ attributes added...though that is also happening to pickups...folks deciding ride quality over pure truck ride
For this OP, going to higher class tires will help, but first air the ‘P’ class tires to their max sidewall PSI rating before purchasing new shoes
Next would be replacing the shocks with higher dampening rate shocks. Even performance level, but ride quality will suffer
Normally do not recommend higher torsional rate front & rear anti-sway (anti-lean) bars, but in this case another less costly than a new vehicle. Just understand both = #1 the ride quality will be reduced and #2 the ride quality will also be reduced
Of course, the setup needs to be dialed in correctly.
From having the right torsion bar ratings, to the orientation of the whole setup, which should have the TV returned to whatever front/rear weighting/measurement/etc the OEM’s manual recommends.
The final orientation of the setup should be the above for the TV after dialing everything in and the trailer should be level in its pointing or preferred to have it pointing slightly down
Of course, first weigh the whole setup, axle by axle, both hooked up and WD bars not tensioned
Good luck and report back so others might gleen insight for their setup