Affinity won’t be able to read/translate the edits you’ve done in Raw Power. As every app is different, the way they apply changes is different, thus no two apps will be compatible (except from the same company i.e. Lightroom to Photoshop). If you want to edit in Affinity with the changes you’ve applied in Raw Power, you’ll need to export a TIFF of the edited image from Apple Photos, then open that in Affinity. Here is a good article (written by Raw Power’s Nik Bhatt) that gives some insight into editing RAW images https://tidbits.com/2019/06/14/the-ins-and-outs-of-non-destructive-editing-in-photos-for-mac-and-ios/