Darker shadows after export (alpha)

Hi,

I use the shadow catcher a lot for virtual staging / adding objects in videos. But the biggest problem is that the shadows get way darker after exporting the image to edit them in Photoshop or Affinity Photo.

I could setup a node tree in the compositor but its so annoying to use the compositor for photo editing.

I tried different file formats, color depth and compression but nothing helps. Maybe someone has an idea?

composited in Blender:

edited in Affinity Photo: