Achieving this effect in runtime (deformation + instances)

Short question: what would be the approach to deform a base mesh during runtime, and have scattered static meshes adapting to its deformation?

Long question: I’m trying to get an “erosion time lapse” effect on a landscape. The camera will be static, so it doesn’t have to use the landscape system, so it could be a large plane that fits in the camera view, deformed by a procedural noise. I’ll need to scatter vegetation and rocks dynamically, and they need to adapt to the changing relief. Ideally, I could also change the scattering as well.

Background: I’ve spent a couple weeks looking into how to get this. Spent quite some time trying different stuff and down the rabbit hole with the landscape system until I figured most likely can’t update landscape deformation during runtime (without some major coding chops).
I looked into Virtual Heightfield Meshes and Render Virtual Textures , but doesn’t seem I could get the scattered instances to adapt to the relief, nor to get the deformation to change during runtime.

Put together a demo (Blender geo-nodes) of the concept to make it clear.

Any clues are greatly appreciated.