I’ve discovered a solution that worked for me. In Unreal Engine 5.1, they’ve done away with the division of the World Partition minimap into selectable grid. Now, you have the option to select and load any region using rectangle selection.
Your landscape might be loading in its entirety because the Spatially Loaded checkbox is disabled on your landscape tiles. In my situation, I disabled this checkbox to make the entire landscape visible since creating HLOD for it wasn’t functioning correctly. I couldn’t build a more optimal HLOD for a landscape that was larger than the original landscape tiles. However, I found an effective method to display all landscape tiles in the game while maintaining the ability to load only selected areas in the editor:
[How do I build correct Landscape HLODs in world partition?]
At present, I’ve placed the landscape proxies in a custom World partition Runtime Grid with an extremely large loading range.
I hope this information is helpful and answers your query.