I had almost that exact set up in my last home. I wish I had a pic to share! There was 8’ of wall between door trim top & window trim bottom. My window was a 6’ square with panes like yours & my door had sidelights on each side as yours does. I went creative. I found an ornate iron twin bed headboard in a garage sale. It was white with touches of gold & had a sloped shape from center to each side. It was just about the same size width wise as the door & 2 sidelights. I cleaned it up, removed all obvious hardware, added some gilt paint rubbed on to make it emphasize the lines and design & mounted it above the door. I also had brass door hardware & a hanging light in brass as you do. The headboard created an interesting crown over the door & really added interest to the entry. I did have color on the walls & in area rugs on top of wood oak floors. Not one person ever guessed what the piece above the door was. When we sold that house, the buyer made it a condition of sale that the piece stayed! We were fine with that knowing we had no place for it in new home. So, that’s my suggestion - go creative with an eye catching but lightweight piece hung in that space. It will take you awhile to find ’it’.

Wallpaper?

I would leave it alone. You have the elaborate chandelier, ceiling medallion and the paned windows. No need for more embellishment IMHO.

Maybe lower the chandelier a bit? I can't really tell from that photo, but it looks mounted too high for the space, but it could be the photo angle.

You could do some trim work around and above the door. I have a somewhat similar foyer though my window is closer to the door. I have some lovely trimwork above and around that works with the traditional styling of the foyer. These are some examples (none are mine).

@M Miller and @pricklypearcactus said exactly what I would've said. Trim and lower the chandelier. That's it.