Images are not showing up at full resolution using Photos for Mac
I see that this question has been hashed over on the community bulletin board over a period of years, but I do not see any single resolution that works.
I have a large library of images taken over two decades. Due to its size, I store them locally and back them up onto a NAS drive. Initially, I used iPhoto as the photo manager. It was free and generally did a good job. Later, I migrated to Aperture, which provided photo managing and superior photo editing functionality. A truly amazing program that Apple, for some mysterious reason, decided to do away with in favor of Photos. Since then, I have worked with Photos as my manager and quick photo editing program, pairing it with Affinity and Luminar for fine-tuning.
I had taken some time off from photography in the past year, but came back to it after a vacation this summer. I uploaded RAW images to Photos and placed them in an appropriate folder in my library. Then I went to review the photos and saw that they were all fuzzy-appearing. Clicking Edit brought the images back into full resolution. This solution, however, did not retain itself coming back to Photos for more editing. Worst of all, it appears that the images imported into a slideshow were also not a full resolution (I specified full 1080HD). Fortunately, the images exported to jpeg at full resolution.
This is frustrating in that my initial review of the images I took suggested that they were all a touch out-of-focus. Is this a new "feature" of Photos or is there a way to fix the resolution issue?
Mac mini, macOS 10.15