using only the next and previous buttons that you can go all the way up to page 2615 but if you go in the search bar you can go all the way up to page 2813, can someone please fix this.

The default post index hides any child posts so that people can upload large amounts of images in one go without taking up the entirety of the front page.

This behavior doesn't apply to searches and is why the two methods feature different amounts of posts (and pages)

It's not a bug, it's a feature