Volumio
Will run on a dedicated raspberry pi and x86.
(dedicated means, the computer will only do this, nothing else)
Connect the sound out of the device to the amp and it will provide a web interface to directly control playback.
Music is not streamed, it can play files from a local disk, or from a network mount.
The free tier is 99% of what someone needs.

Moodeaudio
Same as above without fees, though explicitly only for raspberrypi and a limited number of SBC's

A key fundamental for any music is the metadata tagging and Musicbrains Picard is the best way to do this
Picard can automatically find the proper metadata for almost everything, and, can "scan" ripped from cd tracks and automate the naming and folder structure that a music library should be in.

And as others have said, rip to flac

Meta is not in the hardware business, they're in the software and data transport business.

The hardware is just an intermediary step while they wait for someone else to take on that burden

As far as I can tell I was replying to you, I agree that NMS had those things at launch

If things continue the way it has been, never would be the best estimate of a release date.

Depending on the last time you logged into a session, the current status is between playable and entertaining and nightmare of lag/desync issues making it something most people would want to avoid

In a purely technical sense, if CIG locked the code branch and set 100% of the creative teams to the task, the current system could replicate a Starfield level game and do so in a seamless manner.

It wouldn't be without issues but something I consider plausible

I have a strong suspicion the project will fall to development hell and never really be completed in the sense other games are.

A good point, and the popularity and sales of NMS reflect that

Star citizen has been able to do "all that" for at least 4 years, and most consider it a glorified tech demo

In Star citizen you can also do all those things with other players too

If you think "they aren't close yet" it might be worth trying it out during one of the free fly events - the only cost is your time to download and play it.
Having an opinion is fine, having an informed opinion is better

Syncthing can realtime monitor a folder that just has the keepass file and automatically update to any other syncthing enabled devices in near realtime.

Additionally it can be set to keep versions of the file so you can have copies of older versions to hand whenever things go wrong.

The only real catch is to not have the keepass db open on 2 devices at the same time as any changes made in one may be overwritten by the other as file locking isn't a thing in this method.

I've used Syncthing and keepass in this way for many many years