What does "medium-sized SUV" mean specifically?
First, the weight rating of the hitch means very little. Just because a 3,500 lb hitch is installed does not mean you can tow 3,500 lbs safely. It just means that is the maximum weight for the hitch.
Second, the "towing capacity" in brochures and advertising means very little with regard to how much you can safely tow. Ever hear of the phrase "What the big print gives the small print takes away."?
With most tow vehicles ALL weight you add into the tow vehicle (your SUV) needs to be subtracted from the weight you can actually tow. If your "towing capacity" is 3,500 lbs, for example, and you add 1,000 lbs of people and stuff you
may have just reduced your maximum towing capacity to 2,500 lbs. BUT if your SUV's payload was only 1,500 lbs to start with and you add 1,000 lbs of people and stuff, you can easily run out of payload and be overloading your SUV.
Another issue is the axle ratings of the SUV, the GAWR or "gross axle weight rating". That is how much weight each axle can carry maximum including the SUV itself and everything in it. When you tow a trailer the "tongue" pushes down on the hitch as what's known as "tongue weight". The tongue weight is weight carried by the rear axle as well as the SUV and things in it.
If you are towing a 2,000 lb trailer (actual weight) then the tongue weight needs to be between 200 and 300 lbs for stable towing, or 10% to 15% of the trailer actual weight.
The critical term is the "payload" of the SUV and that will change with each model and optional equipment. What you add into the SUV, including people and tongue weight is part of the payload.
Yeah, confusing as heck and that's not even all of the considerations.
As a general rule I would not try to tow a trailer that had a GVWR of more than 1/2 to 1/3rd of the SUV's hitch or tow rating, whichever is less.
If you want more info you can create an account on this Social Knowledge LLC site using the exact same email address and password as you use here. Both sites are owned by the same company so their software will find your account here and streamline the process.
iRV2:
https://www.irv2.com/forums/f45/
On the driver door frame of the SUV there will be stickers showing various weights such as GVWR, GCWR, and GAWR. If you post a picture of that sticker people on that iRV2 forum can give you a much better idea of what length and weight of pop-up could be safely towed.
There are also "stickies" at the top of that link if you want to read more or do the calcs yourself.
One VERY important item: NEVER trust an RV salesman about what you can tow safely. NEVER. You can take their advice but always do the math yourself. Many a person has rolled their truck or SUV and RV trying to tow a trailer that was too large. YouTube is full of those videos from dashcams.
On the plus side we started with a 10' pop-up and had great times with it for close to a decade.
Good luck.