Until the latest AP2 update, Affinity Photo opened .heic files.
Quick convert (select file in finder, right click>quick actions) is an appealing work around because it is quick - but the .heic option for 'actual size' produces a much more compressed image than the option to export as .heic. I have found that some of the quick converted .heics produce pixelated images in Affinity, while the direct import produced much better results.
Affinity has been building a reputation as an alternative to Photoshop. Many users operate within the Mac iOS ecosystem and the current image software produces large, high quality files. Disabling this capability away does not reflect well on the reputation of the software.
Affinity Developers, please restore the ability to open .heic files directly in Affinity. I am also waiting for the capability to export as .heic, as this is one of the best file compression systems.