Now, I am not sure to have made a correct interpretation of what you wrote.
What does that means ?
Currently, what is edited in UVEditor is active UVmap channel for all objects selected.
If you change active UVmap in UVmap channels list for any object of selection, you change what is displayed in UVEditor.
Currently, when a second UVmap is added to a mesh; this second UVmap is a copy of first UVmap.
If you enable Magic UV addon, you can copy/paste UVs from one channel to another one.
So, at what step a second UV channel would be created to match what ?
How user have any control if that is automatically happening, each time, he enters edit mode or switch to UV Editing Workspace ?
Are you sure what you are requesting is not covered by Magic UV addon that will be bundled with official release of Blender ?