I recently set up Navidrome for this. It scans your music (and audiobook in my case) collection and serves it all up via an HTTP interface. There are apps for Android and iOS.
For remote access the best option is Cloudflare Zero Trust. I know, the Evil Empire, but they provide a useful and free service where they act as an HTTPS proxy for your home server, via a VPN connection. They support various authentication methods too, so your server isn't exposed to the internet, their proxy is.
Anyway, with that I have hundreds of gigabytes of music and audio books that I have collected over the years, accessible from anywhere, and it costs me nothing.