The TLS 1.3 flag...there is a drop-down menu in chrome://flags which allows you to pull up your preferred option. I did a simple CTRL+F search for "tls 1.3" and selected "Enabled (Final)" from that list. (This only applies to v11, as the TLS 1.3 flag was removed from v12 and v13 [since those browsers have TLS 1.3 fully integrated and activated out of the box].)
EDIT: The name of the specific flag is #tls13-variant and the specific option is Enabled (Final).