I recently installed Ropieee endpoint connected to Mytek Brooklyn dac. I have check roon bridge running on Ropiee and it has recognized the DAC using USB.
On my Mac Roon does not see any audio device, I am on the same network as Ropieee. Ropieee is on the same subnet and connected.
If I connect Brooklyn directly to my Mac, it works fine.
Make sure the Mytek Brooklyn DAC is powered on when trying to enable the zone in the Settings > Audio screen. The zone will not appear if there is no active audio output in RoPiee. If you are still unable to see the RoPiee zone, I would suggest power cycling the Mac running Roon Core, the router, and RoPiee.