Apply Variable Mode across collections

I would like to apply a mode on designs across all variable collections. I separated colors, radius and spacings in different collections when creating the design library. Now I can only apply a mode for colors OR radius OR spacings – but not all together.

One alternative option would be to move variables between collections, while keeping the linking to components and designs. So I could merge colors, spacings and radius to one collection.

A consistent structure for collections was already requested 3 years ago: