The most important thing with Roon is that it is Roon Ready. Otherwise, the task it has to do is very simple. If your your DAC reclocks the USB input, the only thing the streamer has to do is accept ethernet traffic via Roon Ready and play it out via the USB-to-DAC (assuming that this will be your setup). If you want to use it via wifi, the wifi should be good. Otherwise I would go with whatever has the features I want and is cheap.
An Raspberry Pie with Roon Bridge installed is probably the cheapest option. Or an iFI Zen Stream, more plug and play and more expensive