Yes and no.
Godot's GDscript has no support for changing variables across all code.
However Godot is designed to work from the main scene down. So using groups you could have one main variable in a parent object, that you only have to change once.
GDscript is a infant coding language with only the bare basics, doesn't even support cases yet.
It is never going to be as useful as C# or any well developed scripting language, it can't be because making a language is as much work as making a whole engine.
I believe that GDscript will eventually fade into a visual scripting language and C# will replace it in the long run.
Sorry for taking this long to reply, I was never informed of your comment.