So after a lot of research and wrong answers, I found the solution in an obscure post. In macOS Big Sur, the path for the icc profiles for soft-proofing in Affinity Photo is "/Users/Me/Library/Containers/Affinity Photo/Data/Library/Application Suppor...
I know this is an old post, but want to thank you for your hard work in figuring this out. Unfortunately, I followed it exactly and copied those profiles to Colorsync, however, they still do not appear in Soft Proofing. I rebooted and restarted, but...