After several tests of raw development using Nikon NXD and Lightroom, the Afinity shadow recovery slider should not be touched. But in better news, it need never be.
The highlights slider is better, but again treat with minimal adjustment.
Best approach for recovering shadows (and highlights) is the balancing of exposure & brightness adjustments using the tonal masks/shadows selection for the shadow area in the photo persona. The masking feature of AP is *excellent*, especially the blending (aka "blendif") function compared to Lightroom.
I use a Nikon D750 which is renowned for recovery from several stops under exposure and I am happy to say the "shadow recovery" results I achieved without touching the shadow slider were *very good*.
Overall I find Lightroom too punchy and saturated in its interpretation of Nikon NEF files with Nikon's own free software NX2 producing far better results, as you would expect. Nikon's Capita NSD editor also works fine if you can put up with the crashes, but lacks the power of many paid for editors.
I have actually now bought Affinity this week following satisfactory results being achieved without shadow recovery and despite the inability to save raw development settings.
For raw processing in the develop persona, my workflow is very minimalist with global & local adjustments now put through the Photo Persona.
This suits my genre (landscapes) but clearly Lightroom is better for batch processing high volume images if you are a wedding photographer.
In fact Affinity may actually help me produce better developed images as it is slowing me down, and making me think carefully abut each step. In Lightroom, I became very formulaic and probably did not get the best output from my raw files.