I have been towing a 28 foot Airstream Camper (~6500 to 7000lb. and ~1200 lb. TW) since 2015. I first towed with the '14 Q5 TDI and it towed well but could feel loose at 100kph+ (62mph), you have to be precise with the weight distribution.
Now towing with the '14 Touareg. This feels much more planted than the Q5 did and more forgiving. I would think the Touareg and the Q7 are very comparable in performance.
Jut FYI, on both of my vehicles I have had the factory Tow hitch reinforced considerably. This reinforcement helps to project the TW more forward on the TV and lessens the stress of the load on the TV too.
For some great information on Towing with SUVs and other smaller TVs have a look at
https://www.canamrv.ca/towing-expertise/ .
Kevin