TLS internally does not depend on a domain in the DNS sense, it basically certifies a chain of signatures bound to a name. That chain can be verified, starting from the root servers.

The problem is more in the fact that TLS assumes creation of a long-living connection with an ephemeral key pair, while DNS is usually a one-shot interaction.

Encrypting DNS would require caching of such key pairs for some time, and refreshing them regularly but not too often. Same for querying and verifying certificates.