I am guessing this is a no, as the exact scenario was requested and the moderator responded with 'possibly coming soon' over three years ago (
I use Capture one to organize my photos, and process Raw images. I often shoot panoramas in DNG (Raw) format from my drone. I can process these raw files, select 4 or 5 and 'edit in' Affinity photo. C1 then generates 'scratch jpegs' that it sends to AP and they open as five separate windows. However, there is no way for me to select these open windows as the source for a panorama. The only option is to click 'add' and search in the finder for files on disk. This breaks the worklow completely. These processed jpegs have not been manually exported, but where generated 'on the fly' by Capture one via the 'edit in' command. (They don't exist on disk)
So, at the moment (and as others have obviously had to do for years now), I have to manually export the variants from Capture one. Create a temp folder to hold them. Point Affinity Photo at that temp location to add those files (which it ALREADY HAS OPEN!) Create, crop and save the panorama to disk. Go back to Capture One, import that panorama into the catalog. Then go to the finder and manually delete the (unnecessary) exported variants, then move on to the next set. Ugghh
All of this could be avoided by enabling Affinity Photo to use it's own open files to source a panorama.