HTTP/2 multiplexes over TCP; HTTP/3 runs over QUIC (UDP) and avoids head-of-line blocking.
Practical: enable HTTP/3 in your CDN (Cloudflare toggle), keep TLS up to date, and watch TTFB metrics. Most users quietly benefit—no app changes.
HTTP/2 vs HTTP/3 — practical upgrade notes
QUIC (HTTP/3) reduces head-of-line blocking; most CDNs support it — flip it on.