As anticipated in the title when you access the share menu in the camera roll you find three identical icons of Affinity Photo as options
UPDATE:: no option for Affinity Photo in the share menu when you choose only one or just a few pictures. After selecting multiple photos the issue occurs. So... no way to Share 1 single element to Affinity Photo from the Camera Roll, or.... confusing options when selecting multiple elements
iPadOS 13.1.2 beta on iPad Pro 12.9 2018