Most full sized SUVs use the same drivetrains and frames as their 1/2 ton counterparts. Toyota, Ford, GM. What is usually different is the suspension. Some knock SUV suspensions, but SUVs often have air suspension, which is a real plus.
Empty full sized SUVs also tend to be heavier than their truck counterparts, assuming the payload numbers work this can be an advantage too.
So to answer your question, in the sizes you’re talking about, there isn’t any reason why a 1/2 ton truck would tow better than a full sized SUV with similar payload capacity. It might even tow better.