Bots already exist to which you can give a URL and they will reply with:
- the whole website in a zip
- the whole website in a webxdc
- the bare HTML file content without styles in an HTML message
- the page rendered in a browser for a few seconds, snapshotted into a small static HTML message
You can find the source code and hosted instances for most in:
https://deltachat-bot.github.io/public-bots/
This specific bot seems to be doing exactly what you ask for: