> faster in terms of time-to-first-byte

Yes, but all these approaches are optimised for long sessions, not TTFB. If that were very important (say, ecommerce) you might prefer a framework that can hydrate and send the full page on first request, rather than setting up a socket to get data.

> data:value\n\n

I believe the poster was referring to requests from the client to the server having to traverse the HTTP stack, not data coming down from the server via the SSE stream.