Because the space is so narrow I would place something like this to cover the old door. You could have a lamp on it. Not sure about a mirror. check it out on wayfair

Push a tall boy dresser against the white door and use the drawers for shoes. Hang a mirror on top, add a fern and a little lamp.

I love storing my shoes near a front door in a vintage dresser.

You definitely need some type of big furniture in front of the old door. As is, it looks strange because it’s obviously a hallway to another room.

Or, if that doorway probably will never be reopened you could remove the door + trim, then sheetrock and wallpaper so it looks like the rest of the space.

Beautiful wood! Glad you’re not painting it.

I grabbed this from Ballard’s just to show an example of something tall there (it’s not to scale). With all of your lovely stained wood, I like the idea of a light painted cabinet with glass front.

I adore this old cabinet and if you could find something similar, you could hang art above and have a lamp on top:

On the left wall, sconces could work for lighting instead of a lamp, and a mirror to reflect light and add dimension to a tight spot. Not this style, just showing placement:

These suggestions are just going by what little we’re seeing. Can you show other angles? Other lighting in there, what your front door looks like, any rugs nearby, etc.

Thank you for the photos! love the vintage piece and the hallway photo is a very helpful visual! Wallpaper is an interesting idea. Agree that something tall is needed.