Towing mileage/capability

First, I did see a 'what are you towing with?' post. Be darned if I can find it. I'm happy to read suggested posts if you point me to them.

We have a 2021 Wolfpup 16fq, 3200 lbs, nearly 12' high if you include the AC; figure 4000 max with us and fuel and gear.

Right now I'm towing with a 2003 Yukon, but in a year or two we'd like to get something better - better mileage the priority, but failing that, capability and/or comfort, as well as lower to the ground if possible, as my wife has problems climbing into high trucks. So I'd like to hear from people with experience relative to our trailer, if possible.

I work on my own so older vehicles are worth considering, too. My experience is, rated towing does not always align with capability, and while I've found 4wd is helpful at times at county sites, I wonder if front wheel drive - like the Flex (4500lb tow) or the Traverse (5500lb tow) are up to the task.

Our experiences:

My Dakota supposedly had a 5500 lb rating (3.57 ratio and 135k on the V6) ; I had upgraded brakes in anticipation of towing since it had the towing capacity. It manhandled the trailer fine and actually brakes better without trailer brakes (yet) than either of the GM full size. However while mileage here in the rolling hills of eastern Iowa was 14, it wanted to spend most of its time in second gear which made me a bit nervous. I suspect a V8 one would be fine. Very comfortable on long trips.

We bought a 2001 Silverado Z71 with the 5.3 V8, 4.10 gears, trailer package but while replacing the brake lines found a cracked frame covered up with undercoat and the rear axle leaked Iike a sieve; we replace it with the Yukon (340k) also with the 5.3 and 3.73 gears. The Silverado towed well, rarely went out of overdrive, and got 14/21 not towing, 12 to 14 towing, and climbed those steep hills along the Mississppi. By contrast, the Yukon will only tow in third and wants to shift liberally to second; mileage at best is 10/17 not towing and 8 towing, on the same roads as the Silverado; it struggles on steep hills. Both of these newer trucks kill my back. Actually the '95 Silverado K1500HD (trailer package and 350, extended cab long box) towed and got better mileage than this Yukon does with the '71 Holiday Rambler Vacationer we had some years back. That truck was much easier to work on, too.

So what are other's experiences with towing trailers around this size? Are there better choices without spending a huge amount?

Thanks, Bruce