I made my own web app using boring technology(1). It's not available anywhere since it's completely tailored to my own needs so probably not useful to anyone else. Also some parts of the code need cleanup and there is no documentation.

(1) SQLite/Django/Bootstrap5/Unpoly app. SQLite is used for all the data and the full text search. Huey is used for background tasks. Tinytags gets metadata from audio files. LastFM API provides similar artists functionality. YT-DLP is used to fetch music that is not easy (for me) to get (no bandcamp, only on streaming, old stuff not easy to find...). Bootstrap provides a clean look and the usual responsive stuff. Dropbox API is used to maintain a copy of the music files in my dropbox account. The app currently handles a collection of 70k files and runs on a raspberrypi behind the caddy web server.