Wow, you have a narrow tunnel. I would try to visually widen it and move light into it by adding decorative mirrors. There also seems to be no destination, so I would make the end of your tunnel a focal point with paint maybe or a colorful runner. Love the arch. If I could afford it, I would also remove the banister wall and replace it with a railing to visually widen your hall to include the stairs visually. What is up with the gift ribbon hanging from the letter along the staircase? Is that on purpose?

Not sure what you're going for, but DITCH the bows , please.

IMO ditch all the stuff in the stairwell , everyone knows it is your home. As for what on the other wall none of what you have there . maybe a series of photos all in the same frame maybe darker in your case.