With the new support in Affinity Photo for Astrophotography, it seems like this should be possible (but I'm new to AP, perhaps it already is)... So, I'll describe what I think should happen. I'm working with a large number of images, over 400, and would prefer to keep them in DNG format. Why? Because then I can make local adjustments to key images, and then apply those to adjustments to a whole batch of images in one single operation because the images are aligned.
What I think should happen is this:
(1) Point AP to a folder that contains all of my DNG files and say "Align Images" (as it does for Astrophotography)
(2) Apply a crop to all images so that the visible area of the DNG files are aligned and then save those results, so I now have a collection of aligned image files.
It seems like most (if not all) of the technology to do this is already in AP with its recent Astrophotography tools, but the workflow and result is different. It also seems to me that the load many files as layers to align them in a single "master" file is not quite the right solution as I'm talking about dealing with hundreds of files not a few.
Thanks - hope that all makes sense
William