Hi friends. This is a solid waste of money. I run my own Intel NUC with an external HDD array with 6TB of raid 1 storage. The NUC itself is a few generations older and i5 based but it was less than $400 . The Roon Rock OS itself is free but the subscription is either $12.99 USD per month or $699 per year. I don’t use Roon myself as I have windows on the box and use it to serve my old DVD and CD rips (from my library). Frankly most of the time the box is playing Amazon HD Music streams these days as both the convenience and quality are there.
For a sound card...as an audiophile, we usually use an external DAC via USB or coax/to slink then into our external amp(s). In my case, this part of the setup is where the money went.