How Break map into Plates/Parts/Blocks?

[ClockworkOcean]

You can use level streaming, either done using blueprints, or volumes. There is also World Composition.

HTF do I? Level Streaming using Volumes in Unreal Engine 4

But much easier to change to UE5, then all of this is handled for you automatically slight_smile:

UE5 World Partition / Getting Started Tutorial