Error Message when Packaging: InNumLeafObjects <= MaxNumLeafObjects

Hi I am getting an Error message when packaging my project, and I am struggling to find any resources online. Did anyone ever experience something similar:

UATHelper: Cooking (Windows): LogOutputDevice: Error: begin: stack for UAT
UATHelper: Cooking (Windows): LogOutputDevice: Error: === Handled ensure: ===
UATHelper: Cooking (Windows): LogOutputDevice: Error:
UATHelper: Cooking (Windows): LogOutputDevice: Error: Ensure condition failed: InNumLeafObjects <= MaxNumLeafObjects [File:D:\build++UE5\Sync\Engine\Source\Runtime\Experimental\Chaos\Private\Chaos\ImplicitObjectUnion.cpp] [Line: 116]

(And then some Callstack Errors)
UATHelper: Cooking (Windows): LogOutputDevice: Error: [Callstack] 0x00007ffc8f525dc7 UnrealEditor-Chaos.dll!UnknownFunction []
etc.

I am trying to build a Large Landscape (10km x 10km), with buildings, roads, railtracks and rivers