I went through the same process a couple of time. In the end, determined I needed a dedicated music server, streamer and DAC. Decided to get a DAC / Streamer combo to cut down on cables and avoid the USB questions. I run ROON and source music from Qobuz and my personal online music library. Pretty much committed to streaming. A bit over your budget (maybe not preowned) but I ended up with:
Bacasti M3 w/ network card - looked at Lumin but decided to stay local.
Small Green Computer - sonicTransporter i5 w/ 4TB SSD
Overall I'm really happy and back to listening and discovering music instead of chasing equipment.