I think I would do some sort of built in, with "fake" doors on the bottom to resemble cabinets

I would put a comfy bench in front of it and use it as a book shelf. Stage it with some books a nice plant, candle sticks, etc. A cozy little reading spot. Paint the wall and finish the trim. Maybe a nice piece of art on the wall above. You can pickup a bench or even a little loveseat for cheap money. Some pillows, a throw blanket, or a single chair.

Hi Sammie J! Thank you for the reply. I actually really like this idea and the doors would help with the awkwardness of it.

Thank you for your reply Paula Cushman. And I like this idea too. Originally I wanted to install some floating shelves but the space just seemed really deep for the shelves. But the way you explained the set up makes it seem really nice and cozy too!