Best Digital Music Server

I would try and look at a Bryston BDP-2 (audition).  The new 3s are crazy expensive.  But the 2 can be had for budget.  I just got the little Pi unit and cant believe how good the SQ is.  Manic Moose interface is  pretty lame though :(.  Only supports Tidal and Qobuz but can be used with Roon as an endpoint.

Trying to be helpful, but if you’re on a different track, maybe it doesn’t seem that way. But please realize, no piece of hardware that has ripping will give you the ability to fix metadata like JRiver’s software will, or dedicated metadata programs like PerfectTunes. And of course, one of Roon’s main reasons to exist is that it manages all the metadata so you don’ t need to.

And I doubt that many hardware boxes with ripping will give the same kind of quality control of the rips as JRiver, dBPoweramp, or Exact AudioCopy. All have systems to ensure that your rip has no errors. Another advantage of dBpoweramp is that it draws from five online tag databases, so you can get the metadata right and as you want it from the beginning.

Another issue with one-box systems is that a CD that won’t rip error-free in one optical drive sometimes will in another. It is nice to use a method that allows you to try more than one drive.

Unfortunately, a lot of the language around computer-based audio is very loosely used by audiophiles, reviewers, magazines, and manufacturers, leading to confusion, or at least lack of clarity. I’m not sure what you mean by "server." A file-storage box with GUI to put on the audio rack and connect via USB to a DAC (or analog cables to a preamp)? Or something connected over the home network? Or something else? (To me, a "server" is software running on a storage device. Something that gives USB out is a "streamer" or more accurately, a "stream renderer." But I know not everyone uses the terms that way.)

Either way, I can recommend the Auralic Aries G1, which is in your price range. It will stream files from various sources, including an attached USB drive, and provides USB output (and others). I get outstanding audio quality from it. Auralic's new firmware, lets you attach an inexpensive CD drive to it via USB and rip or play CDs. It even has DSP that you can use (or disable) to resample or add EQ to control bass nodes, for example. I have an Aries G1 and like it a lot, despite my preference to rip the files another way. You can find many reviews on the Web.

Or just spring for dbPoweramp on your PC.
No unknowns (except for unpublished).
No missing tracks or artwork.
SACD (DSD) does sound better. You can rip them easy except for art.
Of course not on any 'best' server.

Of course?  Baetis includes dBPoeramp as well as JRiver.

A lot of good suggestions here.  I do recommend you get something that is Roon compatible, it is just too useful a database to skip that feature.    Even if you don't plan to use it now, you can get a free trial and you might prefer it.   

Exact Copy is software you can buy for your PC, a lifetime license is dirt cheap, and it makes a bit perfect copy in either WAV, FLAC, or some lossy formats.   It is pretty good about finding the Metadata too.   It is more manual than the Bluesound Vault 2 I bought but I didn't find the BS Vault to be any better, other than being more convenient.  SQ is the same once you are in a WAV format.   

FLAC is not lossy but the streamer must uncompress the file on the fly and with a slower processor, it might make a mistake now and then.   I do believe that is the reason some folks believe WAV is better than FLAC but both are not lossy formats, so they should sound the same if the decompression is correct.    

I would agree with @mike_in_nc . I also own an Auralic G1 (as well as the DCS Network Bridge) and have previously used their Aries streamer. The wifi capability makes it very convenient for me and it has all the streaming options I want. Their Lightning App is very nice and you can also use their Lightning Server, although I use Minim Server running on a Synology NAS instead. As for ripping, for years I have been using a Mac Mini with XLD or dBPoweramp, FLAC files only, and for editing the metadata I use Metadatics. I am sure there are some very good one box solutions out there, but I like having the flexibility of separates.