However UDP is preferred as it gives a better experience.
Please explain.
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Based on your research, it seems you are experience packet drops. During packet drops the behavior is different between UDP and TCP.
With UDP the whole transmission stops as you can't retransmit the packet while TCP will retransmit the dropped packet.
You need to check every interface on devices being used in the transit path (FW, Router) for congestion.
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Edison.