In the form of a key map. How can I make the type of a variable change depending on what is selected?

In the form of a keymap like in the image,
Is there any method or plugin that would change the type of variable on the left side depending on what is selected?

As for the application.
In the current scenario
Changing the parameters of an object
Overriding the structure as it currently is
I wanted to change only the specified variable, like a member variable of a structure.

BP only as much as possible.
Or, I want to keep it simple by installing plug-ins, etc.