Do not assume HTTP/2 fixes request ordering
HTTP/2 removes several HTTP/1.1 connection constraints, but resource discovery, server prioritisation and main-thread work still determine when useful content appears.
Keep critical resources discoverable
Place essential styles and the primary content in the initial response. A multiplexed connection cannot request an image, font or script the browser has not yet discovered behind client-side rendering.
Inspect the implementation
Browsers and servers express and apply priorities differently. Use waterfalls and protocol traces to observe real ordering through the CDN and origin instead of inferring it from the protocol label.
Remove legacy workarounds selectively
Reassess domain sharding, concatenation and inlining with evidence. Some HTTP/1.1 techniques add DNS, connection or cache costs under HTTP/2, while indiscriminately splitting every small file can create new overhead.
The negotiated h2 protocol confirms transport capability; it does not prove that the most important bytes reached the user first.