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
-Ben
Picture of my rig1996 GMC SLT Suburban 3/4 ton K3500/7.4L/4:1/+150Kmiles orig owner...
1980 Chevy Silverado C10/long bed/"BUILT" 5.7L/3:73/1 ton helper springs/+329Kmiles, bought it from dad...
1998 Mazda B2500 (1/2 ton) pickup, 2nd owner...
Praise Dyno Brake equiped and all have "nose bleed" braking!
Previous trucks/offroaders: 40's Jeep restored in mid 60's / 69 DuneBuggy (approx +1K lb: VW pan/200hpCorvair: eng, cam, dual carb'w velocity stacks'n 18" runners, 4spd transaxle) made myself from ground up / 1970 Toyota FJ40 / 1973 K5 Blazer (2dr Tahoe, 1 ton axles front/rear, +255K miles when sold it)...
Sold the boat (looking for another): Trophy with twin 150's...
51 cylinders in household, what's yours?...