Hi,
I think this is related to an issue where the Chaos Visual Debugger remote session discovery system was active from editor start up instead of only being active when CVD (for short) is open.
CVD sends the session discovery ping once per second, and target applications (other editors, game servers and game clients) only answer when they get the ping. But I do see how the traffic can increase exponentially with multiple editors open in the same LAN, as they will be discovering each other.
A fix for that problem was made a few months ago, and will be available in UE 5.7.
The system doing the ping is not part of the ChaosVD plugin, so disabling it will not fix the problem either sadly.
https://github.com/EpicGames/UnrealEngine/commit/2e0db326b11c298ca8a3d57b3d82293ae88e8b05
As for a workaround, the only one at the moment is disabling the UDP Messaging plugin, but this is not an issue with that plugin. Disabling that plugin might/will break other functionality that depends on it. For example, in the CVD side, CVD will no longer be capable of discovering a packaged game client or server running in the same machine or LAN (which for this case seems like an acceptable trade off). Other tools might be affected differently.
Apologies for the issue