Reply To: no result on displacement map
Okay, the confusion is completely understandable.
So, I opened your file in 3.3.2.
Shapekeys > down arrow > New Shape from Mix.
Delete the Shapekeys one by one, the New Shape last.
Set all subdivision levels to 6 in the Multires and Apply it.
Add new Multires and Generate > Rebuild Subdivisions.
Bake the Displacement.
Here is the comparison of the two heads, both using the same Image Texture (the displacement is of course calculated according to the rebuild head, which is slightly different from your original):
