Internal Storage Showing Really Confusing Data

I have been noticing that my iPhone was getting slower and went to check if my internal storage was full.

Now I am really confused with what is showing to me and after some research I didn´t find my answer so I kindly ask for some help here.

My iPhone tells me that in my internal storage 230,53 Gb are being used of 256 GB of total storage capacity. But in the same screen, it tells me that iCloud Drive alone is usuing 251,34 GB which is more than it is saying it is being used. It also tells me that Whatsapp is using 57,39 GB of internal storeage, which adding to iCloud Drive would sum to 308,73 GB which would be more than the capacity of my iphone. How is that possible? What is the real amount being used in my internal storage?

I want to free some space, but I don´t even know where to start from because of this. I have been deleting photos in my icloud, but I don´t even know if thats doing anything.