I just watched this video comparing Affinity Photo, Photoshop and Photo RAW's advanced blending capabilities.
PS has Blend IF, PR uses a combination of features and our dear AP, of course, has Blend Options. Although the author declared that no one approach is better than the other, I disagree; it's clear that you can do much more with Blend Options than you can with Blend If.
I've watched several tutorials using Blend Options, but none of them touch the curve in the right panel. That's the only panel used in this tutorial, and what you can do with it is pretty cool. I've attached a file containing the layers he uses in the video so you can play along.
Now that I know how to use Blend Options to simulate Blend If, many of the PS Blend If tutorials available from the same author are accessible to AP lovers. Check it out:
https://f64academy.com/advanced-blending-photoshop-on1-photo-raw-affinity-photo/
Gray Zones.afphoto