Deleted 29gb of photos and my total storage went from 61gb-60gb, this is ridiculous

I’ve been noticing that it almost doesn’t matter what I do on my phone to clear up storage. Roughly half a year ago, my

phone started telling me

its storage was full, since I have an iphone 12, I accepted that and made some changes.

However, about a month ago my phone stopped a download because I didn’t have enough storage, so I went to delete some videos that I moved to another hard drive previously. It allowed the download, but I noticed it didn’t remove as much space from my total storage as it did

from the storage it said photos was taking.

Two days ago, I got curious so I started transferring and deleting all my photos from my phone. I deleted about 29gb total. My overall storage went from 61gb out of 64gb to about 55gb, then back up to 60gb?

This makes no sense to me and it seems as if my phone is

lying about how much storage I’m actually using. Please explain what is going on.