In my opinion tire pressure is a personal choice
Tire makers have their opinion for best wear and longevity, but they are not the ones driving the vehicle
Ford also has their opinion on the stock tires, but once the vehicle is sold they are no longer in charge, you are
Tires are the first line of defense for bumps, springs are the 2nd, wrong shocks are the 3rd
Shocks do not support the vehicle, they are there to dampen spring deflection and recoil, that's all, if you put "stiff" shocks on, the springs can't do their job, absorb wheel up and down movement without passing it on to the frame/body
With both shocks disconnected on an axle you should be able to move(bounce) the body/frame up and down easily, but it keeps bouncing because there are no shocks
With shocks added should be just as easy to bounce but won't keep bouncing
If its way harder to bounce then wrong shocks for smooth ride
If its "stiff" with no shocks then its "over-sprung", the spring's weight rating is too high for the weight of the vehicle on that axle, this is a common issue for the rear axle on pickup trucks because they have springs rated to carry 1/2 ton(1,000lbs) more than their empty bed weight, this can be corrected with lower weight rated springs and then an overload spring added, but costs more so car makers don't do that in most cases
Nothing can correct "over-sprung" vehicles except changing the springs or adding more weight to body/frame so spring rating is correct for the weight on that axle
If shocks and springs are OK, then you can set tire pressure for your preference and driving conditions
If your roads have lots of "bumps" you may want the tires to be lower pressure so they absorbs the smaller "imperfections" in the road surfaces, lol
The lower pressure can effect tire wear so you need to keep an eye on that and use your best judgement
Lower pressure also means better traction, and traction is friction, and friction is tire wear, lol, and friction also effects MPG, lowers it a bit, but just a bit