But you see the Host header after the TLS handshake, after the certificate was sent. The poitn of SNI is to indicate the host header during the TLS handshake so

But you see the Host header after the TLS handshake, after the certificate was sent. The poitn of SNI is to indicate the host header during the TLS handshake so that you get the right certificate. HTTP with the host header is one layer up. Again, this is for transparent proxy where no CONNECT is being sent.