This is my recipe for creating an inexpensive Roon endpoint.
Cheap RAAT usb device.
1. Buy Raspberry Pi 3 B+ ($35)
2. Download Allo Dietpi RAAT ready image (dietpi.com/phpbb/viewtopic.php?t=2317)
3. Use something like Rufus for Windows to burn Allo image to a micro sd (rufus.ie/)
4. Follow instructions to further customize Allo running (dietpi.com/phpbb/viewtopic.php?t=2317)
5. Plug Raspberry Pi into USB Dac of choice (I use the excellent Khadas Tone Board).
6. Use Roon Settings - Audio to configure your new Endpoint
7. Enjoy musical bliss