How to recover missing iCloud photos when 'unable to load photo'?

Unable to Load Photo

I have been experiencing this issue for years now and have lost several hundreds of photos because of it.

I cannot find any solution to get them back. It’s not phone storage, it’s all iCloud. The photos are missing on my Mac and MacBook as well.

if anyone has experienced this and was able to get their pictures back, please help!

[Re-Titled by Moderator]