6 ply or 10 ply. Would I see a difference?

speediq99 wrote:
I've heard the argument that too much pressure on the load bars creates bouncing. I just don't understand why?

My understanding is that pressure on the equilizer bars transfers move weight to the front which helps take the load off the back reducing bouncing. In my crew cab f150 2021, I can't barely compress the front unless I really load up the Equilizer bars.

Truck is new with 12k miles. As soon as it hits 20k, I will probably just add the Load E tires.

MC
MC

From your previous posts, it's unclear whether you have an issue with how your truck/trailer handles or just have expectations that may not be realistic.
That said, more pressure for a given load = less flex and a stiffer, more planted "ride." Within reason.
If you want to test that theory (rvnet psi cops close your eyes for a sec here please), air up your current P/XL tires to the weight your carrying plus some and go fer a drive.
Front, you said is still at factory weight or a bit light, so give 'em 44 psi or whatever the max rating is. Should be well over the min psi for the FA weight.
Rear, air them up to the weight you're carrying + 5-10psi. If that means dumping 55-60psi in your tires, that's fine, don't freak out, tires will not pop. It will stiffen up the sidewalls considerably. Take a test run and see if it helps. Far cheaper than buying new tires to fix a problem that it may not fix.
(I've run OE light duty P/XL rear tires at excessive psi many times for many miles. That's what happens when the boss says you don't need a 3/4 ton, but still have to do your job. I started out "trying" to pop a tire or 2 so I could get new ones. Never worked....but it sure improves handling)

If it works, higher load range tires can/should be in your future. Higher load LT tires will do a bit better than the overinflated donuts as the side walls are also heavier/stiffer. But airing up the ones you have will prove or disprove the need for them.

Edit: This is an as is / no warranty suggestion.