Gilberto. Lots of stuff going on in your post. 1st, when you say "trailer is not level", this means the tow hitch is either too high or too low. Suggest you level the trailer in the street, street needs to be level also. Now Bach up the TV to the ball hitch. The ball should sit approx 1-2 inches above the trailer hitch. When you couple the trailer with the TV the trailer should still sit level. If not adjust the ball height, if you can't get it high enough then get a ball hitch that goes higher. Etrailer has some good basic videos that explain this. I believe that the F250 should not need a wdh, based on what other members have said, HOWEVER, IF THE FRONT AXCEL OF THE TV IS HIGH then a wdh will help.
I suggest getting a WDH / anti sway system that is built as one You can buy separate anti sway bars but why? I would start with the TV / trailer coupling, get that right and you may be done.
Please buy Made in USA