Thanks for the feedback. It looks like just loading the ‘.png’ height map and sampling it in the material is the way to go. I have the landscape min/max world coordinates for its simple to get UV coordinates to sample the texture.
In case anyone’s interested I want to do this so I can dynamically offset vertices in a static mesh to the landscape. Here is an example from Farcry 5, they offset tree trunk/roots to form to the landscape.
Image is from GDC 2018 about Rendering Terrain in Farcry 5.