Is it possible to select pixels in APho by opacity?

[Affinity Rat]

As I recall years ago some graphic software I had, had a slider that could be used to select the opacity of pixels, is there anything like that possible using shades of gray and channels to that end? Barring this possibility any other way.

I am aware of using the menu item select partially transparent but this is of little use to me.

 

[Alfred]

I don’t know of a way to specify the amount of partial transparency (e.g. 15% to 20%) but I think there should be. Only being able to select partially transparent pixels is of very limited use, especially since we can easily select completely transparent pixels and then invert the selection.

[MickM]

I just came to the forums looking to ask the exact same question and found this thread before posting - but all I found was disappointment :-(. Can this feature please be implemented?