There’s something called Adaptive Net frequency. which might be used by the engine to automatically decide to lower the net frequency based on how often it actually needs it.
“… , there is the Adaptive Net Update Frequency setting, which can be enabled with the net.UseAdaptiveNetUpdateFrequency console variable. Once enabled, the AActor::NetUpdateFrequency property is treated as the maximum update frequency and the AActor::MinNetUpdateFrequency property is the minimum update frequency. The replication system dynamically adjusts the Update Frequency within this range depending on how often the Actor’s replicated properties actually change. This feature helps reduce the processing of Actors that don’t end up having any state changes to replicate…” -Matt Gibson
but to do that depending on distance is like dartanlla said " you can implement your code"
but on multiplayer i don’t see much of a sense, unless you always have only 2 users. since afaik the net frequency will impact all players. that means, that, depending on the distance between A and B you are potentially changing how A updates to C,D,E and all others.
if you want to implement an LOD type of thing, i’ve made a plugin for significance, which will easily let you modify any thing you want based on any other criteria, by default distance to an actor.