Best way to play Hi-Res (.flac) files in a theater room without a dedicated computer

Hey everyone - question time. I have a theater room in my house that I regularly use for visual entertainment, but the audio is going to be receiving a big overhaul over the next few weeks and will now serve as a home theater AND a listening room. Because of this I will need to be making changes to how my content is being played.

Right now I'm using a Nvidia Shield as my streaming device, but I want to be able to play or stream .flac files in this room without having to set up a dedicated desktop there. I do have a desktop and a DAC for listening with headphones in my office, and I also use Plex on my shield for streaming movies from my desktop to the theater room.

Is there a good way to easily listen to these files in the theater room without having a dedicated computer? I have .flac files on my computer right now, but I'd also be interested to learn about Hi-Res music streaming options that may work.

Thanks!