I’ve been using Linux for a couple decades now – I use Windows at work and came to like bing desktop; it’s unexpectedly nice.

There’s always Ctrl+R

It could be a music server with mpd – then you could configure it to stream over http to other devices. Or you could configure it as a client for a music server you keep somewhere else.

Just ext4 on my Linux things; I got scared away from btrfs because of some file loss horror stories