How to get the screen rectangle area of a child widget?

I want to place the mouse cursor over an option of a dynamically constructed/modified menu based on events like input and menu opening. I created option widget and menu widget (uses option widget). Menu widget can be child of screen widget (or child of child, or lower). I need to convert options and menus areas (left/top to right/bottom) to screen coordinates (of mouse cursor). How to do it? All my calculations fail. I accept solutions with blueprints but I have preference for C++ (high performance calculation).

I wonder why you want to do it that way instead of using built in widgets but i found out that sometimes coordinate systems are different like how touch coordinates have to be converted to UMG coordinates to get them to match up.
Maybe that is the problem with your calculations is that you need to convert to the same coordinates. You can do this within Tick of the widget class because Geometry object is passed into that tick.