Here is a photo of my Gen 2 crewcab Raptor door jam sticker. You can see Front GAWR 3700, rear axle 3750 but total of both cannot exceed 7050.Can you send the link to where you are finding this information? I have not found much on the ford site. I am probably just missing it.
Now take your Raptor the scales with a full tank of gas, your normal passenger and gear load and see how much you already have on the rear axle.
Then hitch up that 8000# trailer with 10% tongue weight (another 800 lbs), and you are very likely to be over both GAWR and GVWR.
Also attached is the other door jam sticker which says "The combined weight of occupants and cargo should never exceed: 1067 lbs."
So to tow that 8000lb trailer Ford says you can tow, all passengers and gear must weigh less than 267lbs combined with 10% tongue weight.
BTW, these stickers are specific to each vehicle because they factor in what options are on the car. But you can see them at the dealer before you buy the truck.