FUBAR, in terms of speed, but of course. because, TLSv1.3 negotiation capability is there. My server dictates the selection, lest the client gets the sideway

FUBAR, in terms of speed, but of course. because, TLSv1.3 negotiation capability is there. My server dictates the selection, lest the client gets the sideway algo slip. try it through your enterprise TLS transparent proxy. also, no HE IPv6 tunnel.