If you actually want Roon, you do need a Roon Core (server) located somewhere on your home network, doesn’t matter where as long it’s on the same network as the RPi. This can be any PC or Mac that meets the minimum system requirements to run it. Just a Roon Endpoint (RPi + Pi2AES) won’t do it - you need the Core as well. Roon will run Qobuz, but not Spotify. However as @Ksaurav402 says, you can run Spotify directly from the Ropieee XL Operating system if you want, and you control it with the Spotify app on your phone - no Roon involved. I haven’t used Ropieee XL yet, but @Ksaurav402 i assume you need to switch modes in RopieeeXL in order to go between Roon and Spotify Connect as an output mode?