I towed with a V8 4Runner which is the same platform the Lexus is based on. The T4R had a 7200lbs tow capacity. Trailer was 26' and around 6k loaded. Pulled ok but it was maxed out. Biggest issues were the short wheelbase, could make it a handful in the wind, and the hitch receiver maxed at 750lbs.
Based on that, I would go with the Sequoia. It is based on the Tundra platform and is a very capable tow vehicle. Loved mine, wish I still had it. The tt size you are looking at will be a good match if you're not loading it with 6 heavy passengers. As with any 1/2 ton based vehicle, you will be payload limited.