Hey there! Also have a Raptor in Terrain, love the color!
My recommendation for a WD hitch is Equal-i-zer. Good support and offer a lot of helpful tech advice on their products and how to properly setup a vehicle for towing. This will help with sway and aide with minor sag.
When it comes to towing, or any additional weight added, it's super important to understand that it's your rear springs main responsibility to support the weight. Maintaining appropriate ride height when loaded is KEY!
Bump stop extensions will prevent bottom out however if your springs can't support the weight you'll be bottoming out all the time and effectively running into those extensions. Not ideal. Deaver makes HD springs that would be better suited in this case, rather than their non-HD offerings.
Airbags are a good solution as you can fill them up when needed and ensure proper ride height, however this does limit what you can do off-road. If you are looking at keeping off-road performance and not be limited with airbags, you may interested in a set of SumoSprings. Much more affordable than a set of airbags, however from experience they work well until you fully engage the sumo spring - then the rate really kicks up in a linear fashion. Could be jarring at times.
Unfortunately you have a vehicle that was not intended to really tow...it can....but a little give & take is expected depending on what your end goal for your Raptor is. If you want it to be a tow beast you'll sacrifice a little performance, and vice versa. Hope this helps!