WoW I've finally found a way to a solution!
I was struggling with #LibreCad "Making a Photomacrographic Scale under free license"
https://forum.hack2o.eu/t/making-a-photomacrographic-scale-under-free-license/233
making rulers and objects to scale with very high precision was my problem
Solution comes from @concretedog So thanks <3 with #Inkscape
Inkscape Path Effect: Ruler
https://concretedog.blogspot.com/2024/11/inkscape-path-effect-ruler.html