ok, take a deep breath
What is it that you are setting up for? If Fish only, then you need some minor source for nitification bacteria. Rock will suffice surely if you cycle with some amount.
Bio balls, live rock, bumpy surface, what ever is just a place for the bacteria to colonize. Problem with most is detritus build up. Soooo, a display tank with some good rock to build up the bacteria with good flow to keep detritus moving into sump (and caught by some form of mechanical filtration (socks or...) and changed frequently where as you don't have a nitrate factory. A skimmer to get high organics, carbon to get hard metals, etc, and back to tank. It is that simple. If you run a refugium it has a purpose to export phosphate and nitrate (consumed by macro algae), it serves a purpose of that plus the deep sand bed actually can act as a de-nitratification filter as well as ....
if it were me and setting up a simple setup with a sump, i would do live rock (or dead rock and cycle to make live), sump with mechanical filter, skimmer, carbon and return. High flow in tank is for many reasons, so powers heads for sure!
Don't over think this, the process is simple, don't make it complicated