Your Constellation Mini will be your Roon endpoint and recognized as such. So just about any DAC will do, but, it’s always best to buy Roon approved equipment.
Your core and bridge must be on the LAN so the endpoints can be recognized. You will need to use your phone, computer or note pad as a controller. Your Node won’t work unless you make it hardwired to your LAN or you have a wireless router. Wireless connections are subject to music interruptions when playing hi-res files. The USB on the Node 2i is for an external hard drive.
Did you buy more SSD drive. The SSD for the OS most likely won’t let you store music there You have to have music on a hard drive, Qobuz or Tidal in order to use Roon. If you have a hard drive with music on it you can plug that into the USB in port on the Constellation mini. The only output is USB.
It’s a great thing you can get Roon Lifetime since the price is going up on Dec 31st. Cost now is 699.99 US going to 830.00. I went on the Constellation website and the price for your unit did not change when no to Roon Lifetime was selected. Roon controller software has always been free. Sorry, but it looks suspicious. Just lock it in before then. Hope this helps.