My goal was to push this scene as far as it could go on my 4090 taking advantage of the new Nanite Foliage Voxelization in UE5-Main branch.
The result is a scene with over 200 Trillion Polys, scattered with rules with PCG across a 16k x 16k landscape imported from Houdini.
Truly insane this scene can run real-time in editor.