It does matter.

When I connect to my VPN, the network sees that the server name is yahoo.com

It actually connects to my server which sends the request to yahoo.com and then replies with the cert. So the network sees that yahoo.com sent the cert back to my client from that IP address

Then there is a bunch of encrypted communication with timings and sizes that look like I’m downloading stuff over http.

I’d like to hear a credible model of blocking this