Mask guide - Affinity Photo feature suggestion

[cosmical]

Semi-automatic masking / masking guide tool for Affinity Photo

Here is best example i can find (youtube link)  - Zephyr's Masquerade tool is semi-automatic masking tool, user paint guide lines which help algorithm to solve alpha channel.
Its very fast, i don't know for sure how it works, but i would guess that those guide lines descrip to the algorithm textures and colors which are wanted (or/and unwanted) for mask.
This come to my mind when i saw Adobe's new automatic subject selection demo, where user don't have any control, just some kind of lucky button, so i thought serif could make better, and i think this kind of tool would be much better with better flexibility and control. And it should be non-destructive, it could be based on editable splines/vector paths (like freehand pen tool, or affinity design's Pencil tool) for example?

Maybe Affinity Photo should have "Mask persona" (all masking tools in same place, with lasso selection, mask bursh, guide brush, some procedural masking tools? vector tools, refine tools etc.  with easy to use possibility control and edit multiple mask channels for same layer, if layer has multiple mask/alpha channels then mask persona would be great way to control the complexity, at least it would be nice to have way to control multiple alpha layers like separated hair mask, head mask, etc. for detailed and flexible workflow)