Suggested way to create valid tls certificate for turris devices lan address

In a lecture at DEF CON 27 Crypto and Privacy Village - Karl Koscher - Enabling HTTPS for home network devices a way was suggested that leverages a trusted TLD to create valid TLS certs for non routable addresses from lets encrypt

as the turris project controls the domain it can be used to create certs that are valid for turris devices

see the software for it at github

its worth investigating even as a low priority feature