I dont understand this scenario at all. Your hauling a 20 foot enclosed trailer and your Old F150 handled it better and squatted less?
That makes no sense to me. The coils on my 2500 are big and beefy. When I hook up my 23 foot 6k TT with no wdh, I get hardly any squat at all.
I can't see how your half ton F150 squatted less with the same load. My 2017 2500 6.4 has over 3100 lbs of payload and yours should be similar. An F150 with max tow/payload package has in the high 2,000s payload capacity. (Regular cab can be 3,000 or more)
Something isn't right and as suggested, we need to figure that out first before adding airbags and such, which are only typically needed if you push the payload capacity to near its max towing a large 5th wheel or something of that sort.
What are you hauling in the trailer and what is the loaded weight?