iCloud Photos showing greyed out tiles with exclamation marks

Hello, I'm having the most confusing problem.

So, I went to a concert last week and took a bunch of pictures and videos. I don't even remember why anymore, but at some point I got into my iCloud Photos on my PC because I want to take all my concert pictures/videos from the last couple of years and put them on a DVD or flash drive or something like that so I have backups. The problem is that, in iCloud Photos online, 42 live pictures and videos appear as grey boxes with a triangle and exclamation mark (like in the attached picture). Some of them appear perfectly fine and play as soon as I click on them. I cannot play or see these 42 unless I download them to my PC, but what's really weird is that I can still see them just fine in my iPhone photo library.

I have been looking this up and trying to fix it for 3 days. I have called Apple, tried downloading them from Google Photos and moving them to iCloud photos in files, turned off the option for a VPN in my settings, checked repeatedly that they had finished syncing, duplicated the files in my phone to try and sync the copies, and any other fix I could find online. I tried to stop iCloud syncing, deleting the videos in iCloud Photos, and turning sync back on, but I would need to download the full versions of the videos to my phone, which I don't have the storage for. Nothing has worked.

I know that I can download them to my PC and upload them to a DVD or flash drive, but I'm paying for iCloud storage. If I can't really use what I'm paying for, what's the point? If anyone has any tips or solutions for this issue, I would really appreciate it. This has been driving me crazy and I've spent so much time trying to figure it out that I can't let it go. Thank you!