“How to Fix Blurry Media Files in Whatsapp on Oppo Reno 8 Pro with Android 13”

I’m desperate. I’m using an Oppo Reno 8 Pro with Androud 13. Photos and videos that I send or receive in Whatsapp are blurred (irregularly) visible in my chats after a few days and a message appears “Sorry, this media file does not exist in your internal storage”.

But I take some of the photos myself, so they must be in my internal storage, right? Can anybody help me further? I also uploaded screenshots.

Thanks very much