if you are really in to art and styles, I would find two pieces

Large for that wall AND the wall above the ledge on the stair. Do you have a local artist you may be interested in?

Not of fan of hanging art just to fill a space, it should mean something to you.

Two areas to address

What about this other large wall? Do I leave this blank?

These are good spaces for family gallery walls or just a mixture of artwork:

North Rose Hill Scandi-inspired home · More Info

Eclectic Hall · More Info

Last House on the Left · More Info

My vote would be, yes, leave the other large wall blank at least at the stair top level. The 2 walls that Lyn & Beverly suggest you hang art are both walls that a person ’walks into’ & sees on the way up the stairs & when reaching the top of the stairs. Art on those 2 walls would have the most good impact. Hanging art just to fill a blank wall quickly makes for a cluttered look & detracts from great art that might be displayed.

I already have a family photo gallery near the window...so no more galleries on other walls.

I already have a family photo gallery near the window...so no more galleries on other walls.

I already have a family photo gallery near the window...so no more galleries on other walls.

That’s a nice little space with the bench in there. Looks like it’s over entry to home? Makes me want to curl up in a comfy chair with a book & bask in the sun - looks like snow outside!

The gallery you have now looks too crowded. Maybe find something else (smaller) for that space, and use the gallery photos as suggested.

What about putting up an artificial tree?