

This is something that a web designer / developer does. It’s not a Firefox feature or controlled through user settings. However, you are right, that one could probably make an extension that overrides the original setting and forces a different behaviour.



It’s possible that Tailscale (SaaS) or Headscale (completely oss and self-hosted) work for you. This is a vpn based on the wireguard protocol with additional magic. While TS will always attempt to create a wireguard tunnel over udp, it can fall back to HTTPS if otherwise the connection cannot be established. If your motivation is to work from a network where only TLS is permitted this could do.
Tailscale has an Android client. GUI.