Piracy: ꜱᴀɪʟ ᴛʜᴇ ʜɪɢʜ ꜱᴇᴀꜱ

I wouldn't. I like the idea of repurposing old electronics, but the issue is, it's meant to be a low powered device meant to run off a battery.

You can run Plex off a RPi and those are like $20. A bit more if you want the case and heatsinks and such. They are also (similar to the Android) low powered ARM64 computers, but the hardware and software is more open.

I also have an old 128GB Android phone. I use it as a cosplay prop and I treat it like an iPod Touch. I'm primarily an iPhone guy, so of course it has Apple Music on it, but I also know Android and know where Android excels, so it also has Firefox with uBlock Origin, and Nova Launcher Prime. It's way better to type on because the iOS keyboard has always been dogshit.

Also, you're in the Piracy community. Not to be pedantic, but this is where you'd go to ask how to get the files to populate your music streaming server with. That's my weakness there — I mostly self-host stuff I've bought and ripped myself. There are good tools and you'll find good advice here, but something something old dogs, something something new tricks (me being the old dog, not you, unless you are, in which case, good on you for trying to break the mould). Right. So, what you want is the Self-Hosted community. Don't ask them about where to get the music (that's this community), but they can help on hardware and software. Me, I just use Plex, and I host it off a Mac mini. My desktop computer. You don't need to spend nearly that much on a server. My Mac is a couple generations out now, but it's still overkill for a music server.

The only time I use either of my phones as servers in any capacity is to like send a few files or something — and yes, I can do it just as capably with either. Honestly though both of them can easily host a file server another phone (either platform) can connect to and download from.