Best Digital Music Server

This is the same conclusion I am coming to after several years of experimenting with an "HTPC" set-up and several different software options including JRiver (which seems fantastic but also has a clunky look and requires a night school class to master) and lately Music Bee (which I have also appreciated in many ways, but am realizing operating it in itself becomes a hobby alongside the music I am trying to appreciate).  It's not that I mind these tasks, I think it just tries to put our brains in two different places at one time that are not "same sided"..."Damn I truly love this tune...WTF - why is it showing-up as being from THIS album???"  This information exchange has been truly helpful.  Thanks to all who have participated (so far! :))  Lots of product mentions that I need to check into, and now I see that Roon has their own hardware, I need to check into that as well.  I previously felt that Roon was more than I wanted to spend on a service, but I am going to reevaluate now.

@mhwilliford : Best of luck! Here's hoping you'll find something just right for you!

In your price range Small Green Computer servers and Sonore Renderers work very well.  Get ROON.  It is great.  Stretch your budget as much as possible.  You can get a server with a built in ripper or use an external drive.   You can get onboard storage up to 8 TB SSD or just 2 TB.   If you have questions, Andrew at SGC can guide you.  I am presently using their top of the line which cost me about $8K.  They have great set-ups for $2500.   Innouous and Wolf are also great choices.   Use optical isolation to reduce noise......See their websites

The year 2024, now going on 2025. Which is the best-sounding music server that can play FLAC (high-definition lossless) files?

I agree with Soix,  that's what originally attracted me to the Bluesound Vault.  It made PC audio easy.   Then I bought an Aurender and they do an even better job of taking the computer out of computer audio.   Auralic and Innuos too.   Companies with serious software capabilities and solid hardware.  More importantly,  support.  That's what you are buying into. And in most cases a slick user interface.  Worth it in my opinion