i also think your high window at the end of the hall really elongates your hallway. I would put some type of hall tree (but I ? if you have enough room with the doorway there for a hall tree) shelving or art under your window.

Hi there,many solutions to visually widen this area.
https://www.houzz.com/photos/long-corridor-phbr0lbl-bl~l_59834
There are many ideas on the link
But also you can wallpaper one side with a paper that gives depth. Or add mirrors on one side to bring in light

Larger gallery-style art or photos? Rugs on floor perhaps?
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A more ambitious idea would be wainscotting or paneling...
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Or a fun color and pattern...
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I'd paint the walls white (although I do like the idea of a 'depth-giving' wallpaper on one wall too), the end wall in a dark colour. If you're daring, the ceiling in the same dark colour. A striped (width) runner.

Some art under the window could go a long way.

You may want to paint one of the walls in a different color - maybe the wall to the left could be gray. That would be the easiest way to reduce the effect of the narrow and elongated hallway. I'd also try to find a runner in a lighter gray with geometric abstract pattern in white to correspond with the baseboards and the moldings. Find a couple of large framed posters (frames in dark brown finish, same as your hardwood floor) and put them on the gray wall on the left.

White walls, back wall, a fun decal.

HI - First of all, I like the wall color ,but I would paint that end wall a dark charcoal black , window frame too . Then hang a long narrow vertical piece of art or a sculptural piece or maybe a big round disc or a decorative plate or platter, something dramatic and colorful under the window , the window will become less noticable. This will then visually shorten the hall and gives the eye a destination . A hall runner rug in a wide horizontal strip or a texture like a neutral sisal with a border edge. Then add your framed photos or art gallery style . If you want more drama and your brave you could also paint the ceiling the same charcoal . That would make the space intimate and interesting and not boring.

This hallway is screaming for some great wainscoting! Do a quick search for it on houzz for endless inspiration.