iCloud photo issue

I take most of my photos with my iPhone 12. I have my iPhone upload them to the cloud. I can then access them onto my iMac 10.13.6 HIgh Sierra or my Macbook Air 10.11.6 El Capitan. I've done this for years. I also try to take photos at the highest rez possible. DNGs or HEIC. In the past 6 months, when I've gone to access them on one of my computers, the images are completely destroyed. I thought, maybe, my old computers (Photos app) aren't capable of processing the higher res. So, I looked on iCloud. They are corrupt there too.

Photos are worth 1000 words. Here is a screen grab. These are videos or DNGs. The few images that are readable are also DNGs. Oh, they are fine on my phone.