Photos taking up too much space

I have 5726 Photos and videos and my iPhone storage is showing me that it takes up 256GB of space on my 11 Pro.

Just a month before that I had 5000 photos at which it showed Photos taking up 100GB.

When i reached 5,500 Photos it took up 170GB of space.

I have always had Keep Original on iPhone and using optimised storage is inconvenient for me.

Im surprised as to why nearly 6000 photos/videos are taking up 250GB of storage.

Now I have checked again and its increased to 270GB without me adding or taking any photos/videos

I reset the iPhone and then erased it but its still taking the same amount of space.