'cause I did it And what I found did not satisfy me.
The first link Depth Material Expressions in Unreal Engine | Unreal Engine 5.1 Documentation speak about depth expression.
the second link lead us Foliage pixel depth offset - Rendering - Epic Developer Community Forums which is, in my opinion, not a complete answer.
the third llink is an incomplete reply Material pixel depth offset and shadows. - Rendering - Epic Developer Community Forums
Now, I’m sorry If I did not specify that I’ve searched. But I’ve done it. My doubts remains.