Height Map Generated Landscaping

I’m trying to create a landscape to use as a game environment. I made a grayscale topography map to use a the displacement in gimp and a exported it as a PNG. I created a grid plane subdivided to 256x256 and have tried using the displacement modifier with lacking results. Since I’m using this as a game terrain in Unity and I want to be able to edit the geometry later if I need to, I’m trying to avoid using shader material displacement. However, I like the color ramp nodes ability to control the elevations with a curve-like function. It gets better results. So my question then would be, is there a way to get this kind of control while still displacing the mesh in the editor and not at render? Or, can someone tell me why blender 2.83’s A.N.T landscape texture displacement tool does this when I use my height map?

I learned that the landscape tool could use a texture as the displacement, but whenever I’ve tried it this was the result.

Is there a way to achieve the results I’m looking for using the new geometry nodes thing, If so how?