This is very disappointing, the lack of ability for Affinity Photo to create colour profiles from Colorcheckers, and a deal-breaker for me as well. However, Adobe products are not the only ones able to do this. I've been using Photo Ninja, a basic but high quality raw converter, for years and with it you can create light source profiles and camera sensor profiles using various Colorchecker charts, including passports. Photo Ninja can also be set up as a Photoshop plugin so when you've done global adjustments in raw conversion you can just send it to Photoshop for all the extra goodies it provides. It seems Photo Ninja can't be used as an Affinity plugin though. I really want to use Affinity Photo but without colour profile capability it's not going to happen.