ipad dosen't update free memory after deleting 50gb of photos

My iPad was showing that I was running out of storage space.

So I deleted about 50 GB of photos (after disabling iCloud synchronisation).

I updated the operating system,

restarted the iPad,

and checked the Photos app to make sure there were no files in the Recently Deleted section or other folders.

The problem is that it didn't free up any storage space and is still reporting the same issue.

This prevents me from using Lightroom.

On top of that, it's very slow.