Object Material selector in Editor


we need a quick way to change Materials on certain objects/material slots with a dropdown menu
I have a working solution with Materials struct and Enum to do the dropdown menu in the editor details pane. This is in object blueprint construction script

This would need to be repeated for others materials slots/other objects programmatically.
-some objects will have different material choices available
-objects will have different slots names
-lots of possible objects (200-300)
-It is needed in-editor but if possible at runtime is a plus.

What would be a good approach to this?

Editor scripting?

I was thinking to create the additional enums/mat structs and add variables in the various Blueprints construction script if that is possible.
Then somehow adapt the attached graph so it loops through an array of the material slots and set material based on enum…

Does anybody knows how to use this to add a variable to a blueprint construction script?:

I know how to code in python but have trouble understanding how to use the API.