Is there anything like this, except a CLI tool? Something like yt-dlp. I know of curl and wget, but only the basics. I tend to use qutebrowser, which isn't supported, and I don't really expect it to be supported either. Something more neutral run from the shell would be great.

You can run SingleFile from the command line actually :) See https://github.com/gildas-lormeau/single-file-cli