As a result of this very nice site, a few months ago I bought a rpi4 and connected it to my nice rme adi2 dacv2. It sounds perfect. streaming via wifi is really stable (I use ubiquity ap‘s) and I use a standard rpi smps. I tried ropiee and volumio and both I like when using the rpi4 as a roon endpoint. Before I streamed via an onkyo all in one streamer/dac ns6170 ( I think also pretty good and well engineered with dual akm4490 dacs), but could sell it now because of really nice sounding and stable rpi4 rme adi2 combination. The rme digicheck test files I played via roon, rpi4, passed without any problem. So bit perfect And I would really advise positively on the rpi4 as usb streamer, even Via stable wifi.
Downstairs I use a Metrum Ambre decent and 20 times more expensive streamer, but to be honest, I cannot hear a difference. It is really a decent streamer well engineered I think, with nice psu and femto clocks and a connection to the dac bij i2s, utp connection. But I bought it years ago before I found this site ;-)