The filter looks at the SNI header during the TLS handshake. If it doesn't like the host it will reset the connection.
Ignoring ESNI will probably work fine for a good length of time. If pornhub implements it or something I'd probably have to revisit. Or, since I control the clients I might disable it in their browsers.
If enough people bark up the filter vendor's tree I'm sure they'll add a checkbox to drop esni traffic. They added one for QUIC recently.