Technically the quick steel-cut oats take longer to cook, but the steel-cut oats definitely broke down in the water more than the rolled oats. The rolled oats didn’t break down much in the water.
Ones not more refined necessarily than the other. It’s just that one as you go from steel cut to old fashioned to quick oats, they oats get cut down thinner and smaller to be able to cook faster. Steel cut oats have more fiber content because they have the exterior of the oat which is cut down in the other versions. Steel cut oats because they have the harder exterior take longer to digest too so can help keep people fuller longer.
They are about equally unprocessed. The rolled oats have been steamed and then rolled making them already cooked, but they still contain all three edible components of a whole grain. The steel cut oats are just cut from the whole oat so take longer to cook.