Have fun with that space. It looks a bit shadowy so paint the back the same bluey/green as the glass. Add a modern sculpture in black or white. This one is a bit too small but you get the idea.

https://www.etsy.com/listing/1463545181/marble-horse-capriole-statue?click_key=6b2b8c6f5212d894fe77da080f92b35180c761b1%3A1463545181&click_sum=067ba4c8&ref=shop_home_active_2&pro=1

You already have a few too many jigs-and jogs in that space, so I would have it dry-walled over.

This looks like a nice place for a battery operated picture lamp, small canvas, and a tray to drop keys or mail.

It’s just right for a piece of sculpture if there is a bit of light that illuminates the alcove. If the alcove gets no direct light, a light-colored sculpture would be best.

A framed mirror.

How about metallic paint? Then a very small, colorful painting hung in the middle. Could be fab.

If you don't have a closet you could move the country to the other side of the staircase closer to the entry door

I like the idea of a sculpture. I also thought a mirror and a basket underneath for keys.

Shelf, top 2/3rds, with an interesting object, beneath add a basket/tray as a landing spot for keys and mail. Trick is not to become cluttered. If easy add outlet for a charging station.

Wow, thank you all so much for your thoughts! It's definitely giving me things to think about. For better understanding of the space I added a few more photos. And I removed the coat rack lol!!! (it's for the neighborhood kids' things that get thrown on the floor when they come through haha, so really coat rack = joy)

BeverlyFLADeziner the look you put together is gorgeous! I love it! For sure I need to think about adding more textures. We just did some remodeling on our 90s home and we don't own a lot of things so we are trying to work with what we have and pull something together. I grew up in military housing so style doesn't come naturally to me!! :)