Navidrome is a free, open-source music player with a web UI
Here’s a demo site (demo:demo). I was able to launch it in under 30 seconds (M2 MacBook Air, 24GiB) against a ~200GiB music library.
UX and beets integration aside, it’s essentially what I tried to build a long while ago. A simple music player (based on Rust/Golang, SQLite, and simple Web APIs) whose UI made sense to normal and reasonable people and not ambitious product managers.