Hi John - you can do all of this in the open source CloudCompare package. Scale your model to the correct units (e.g. metres) in Metashape Pro first. Export your mesh from Metashape (obj, ply) and open in CloudCompare (where you can also set up real world units). You can use the cross-section tool to generate contours, and the Scalar Field (SF) Tools > Projection > Export coordinates to SF to produce a false-colour plot with scale showing depth distance (if you get your axis/alignment right).
Hope this helps!