I've tried a few options over the years, including SMB and NFS, XBMC as well as HTML with javascript I found online.
I don't have a large collection of music (fewer than 100 albums), so hand coding things was actually one of the quicker options to setup. That's despite then hassle of hand coding the URL to each FLAC file as well as the album art. But sometimes the javascript doesn't handle large collections of FLAC and each implementation I tried had different quirks so I've sunk a lot of time into that in other ways without a satisfactory result.
I've heard of Emby, Jellyfin, Plex, Roon and Servio. I just need something that's simple to set up and access. I don't need fancy features beyond the ability to play the music with a pleasant UI that can be accessed from the web (HTTP, not HTTPS). I'd be running this from a Raspberry Pi 3B which already has the lighttpd server running.
I'm also considering just getting a portable, 128GB FLAC player with a minijack connection and moving on with my life without getting involved in networking at all.
Any recommendations for an uncomplicated way to approach to doing this?
Edit: Thanks so much for the helpful and enthusiastic comments! I tried Navidrome and had it up and running in ten minutes thanks to this tutorial video: https://invidious.nerdvpn.de/watch?v=7V5UUJlSknY
I had to install docker-compose on the RPi. Then I got an error which turned out to be because I also needed a separate docker daemon which I installed following these instructions: https://www.simplilearn.com/tutorials/docker-tutorial/raspberry-pi-docker
In just 10+ minutes I had my music collection accessible from all my devices - thanks again!
Currently I use Jellyfin and found it simple enough to setup. My personal setup is https on the public internet using Caddy as a reverse proxy to handle the https part, but you can set it up for local network access only using http.
Jellyfin itself is not the greatest music player ever, (UI is more setup for movies and tv) but there are music-centric apps that use it as a backend that are really good, for most platforms. On my phone and tablet, I really like Finamp, and on the desktop I use Sonixd.
I used this setup for the better part of 20 years. Nothing wrong with it, my music collection simply expanded to the point where it simply wasn't feasible to store all of it on my iPod anymore and from day to day I never really know what I'm going to be in the mood to listen to. Setting up a streaming service made more sense for me.