What about one of my spare NUC5i3 - fully built NUC, configured to run ROCK out-of-the-box?
See FS: NUC5 based ROCK server
My library is 83k tracks/6,500 or so albums - the NUC5i3 runs fine with multiple endpoints, and down converts any 24/384 or DSD128 or DSD256 without issue.