I don’t know if this is possbile, but anyway…
I often do a lot of layered work with pictures in PaintShop Pro or Affinity. I would find it very useful to be able to see them in the PhotoLibrary, even if I not could open them in Photolab! It would be even better if I just could open them in their native application directly form the library as well.
You say layered work. Do you mean Paint Shop Pro and Affinity’s interim native file formats used for layers? Besides being able to see them in PhotoLibrary you also would like to be able to open them in their native applications directly from PhotoLibrary? Is that correct?
The problem is DXO plugs PL as can be used for Image Management (Access files directly and instantly locate your photos using dynamic search suggestions (New DxO PhotoLab 5)), but omits to point out only those formats it can process. No its not claiming to be a DAM but its publicity is nearly saying that and if it is to be a DAM will have to use formats it can’t process. But the way it is worded is a little dishonest until you know there is this limitation.