[slowstart]

You may be interested in this: https://techcommunity.microsoft.com/t5/networking-blog/makin.... The gist is that yes QUIC has higher CPU usage but all OS platforms are investing in UDP hardware offloads and optimizations to level the playing field. While the only IETF standard that will come out is HTTP/3, our implementation MsQuic powers both HTTP/3 and SMB proving the general purpose nature of the transport. We are not there yet in terms of an application that's only powered by QUIC because UDP reachability is not 100%, so you need a fallback. Most apps will either use HTTP/3 and fallback to HTTP/2 or use QUIC directly and have to fall back to secure L7 over TCP.