You can make some headway with this, but it's a bit painful. You need some fixed presence on the Internet, somewhere, like a server. That can be done, but now you're setting up routing, etc. Or paying Tailscale. It rubs me a bit of the wrong way, since the ISPs job was to provide end-to-end connectivity, and ISPs as a whole are falling down on that … I shouldn't need to build a shadow network in the IPv6 private space …
(And again, we breach the "it isn't worth it" complexity barrier for a cross machine clipboard transfer…)
