Create a real terrain in unity using DEM and ortho image with reall coordinate system

Hey everyone, I m currently working with unity to create a VR application that allows the user (geologists)to interact with the data collected in the field using several sources of the 2D and 3D datasets.

I want to create a real terrain in unity using the DEM and orthoimage for the texture. The DEM results as a Tiff with each pixel associated with the altitude value of the real ambient, whereas the resulting orthomosaic is composed of pixels each representing the RGB color of the real ambient. Both of them have been exported with the same areal extension and pixel size (1m/pixel).

But I m not able to create a real terrain in unity using unity terrain. Any suggestion?

The project is my master thesis. Thank you for your help.