QUIC is a transport used by HTTP/3 and other applications. It operates over UDP and includes its own transport mechanisms. Whether a video session uses it depends on client, server and network support, not simply the stream's resolution.
Avoid universal performance claims
A protocol can behave differently across network conditions, but no name guarantees smoother viewing. A managed network may have policies affecting particular traffic. Use the administrator's supported configuration rather than trying to bypass those controls.
Use a documented fallback
Some clients can fall back to another supported connection method when one fails. The details belong to the application. Do not assume that a television app has the same flags or fallback behaviour as a desktop browser.
Record a narrow finding
If a supported transport option changes playback, report the client version, network and outcome. Keep other settings fixed. That is more useful than declaring that all UDP traffic is blocked based on one unsuccessful session.