I have searched this Forum & the Documentation - apologies if I missed it…
Request:
After masking a subject(s) in order to isolate it from the background (or other objects) - being able to invert the mask to work on the background (or what ever wasn’t selected in the original mask).
Example:
Making adjustments to a human model then inverting the mask so the background could be darken or blurred.
The model has already required effort to mask it (whether masking it directly or erasing it from the selected mask) - why have to create a second mask that will never match up exactly?
Can we create an exact clone of a mask already? This would also be needed for your use case.
In the end all these mask requests will require an adjustment layers panel like the one in PS or Affinity sooner or later. This panel could allow cloning, inverting, hiding, naming, setting the opacity and so on.