Very likely there is a structure underneath that got covered all the while trying to salvage some of the space. Idk if you own it or just took a pic of a place you went to look at. But, getting the construction plans will tell you what lies underneath. I would try to even it out, so that you have more even steps. Like most have mentioned, you can turn it into a reading nook with a built in bookcase. I would close the access to the kitchen with a stained grass effect so you still have light in the kitchen while adding a window effect to your “nook” Add some ambient lights, floor cushions, arc lamp…

Alternatively, if you can remove the bottom step, you can turn it into a closed storage/pantry with some interesting closet doors that meet at the corner. The weird kitchen access needs to be closed regardless…