If you don't need volume control and you use Roon as your interface the Pi4 running Roopie would be fine. The iFi zen is a good choice if you aren't inclined to put a raspberry pi togethe and load an OS.
Point of diminishing returns for a Network Streamers?
You have super cheap Pi streamers (build yourself), $399 IfI Zen, $500 Bluesound Node (no DSD), $700+ Pro-Ject Stream box, then $1k -$2k for Lumins, and others.
I'm running an old iMac as my Roon Core and running a super long, active USB cable to my Dac. I probably do not have to pay much for any improvement since my setup is not ideal.
I'm really fascinated by the Pro-Ject stream box...however...would it be a major improvement over the IFI Zen? I need DSD so the NODE is out of the question .
I could save and go with the new Lumin U2 mini, however....would it be a huge jump over the Pro-Ject?