> Required TLS would also increase security.

TLS is not inherently required for HTTP/2 on the backend.

TLS is sort of required on the frontend mainly because browser vendors don’t want to deal with broken middleware that expects all traffic on TCP port 80 to be HTTP/1.x.

This is less of a concern on the backend, and there are practical implementations of cleartext HTTP/2 today, including nginx and Apache on the server side, libcurl on the client side, and others.