Strange, my original images were removed from the thread. Here are the images of the wall connecting to the lengthside hallway where wainscoting will be installed:

This is the lengthside hallway, picture gallery is hung around 40" (is above the 32-36" planned wainscoting height).

This is the view from the lengthside of the hallway.

I'd want to end the wainscoting at the top of the stairs or the wall of the window. I don't want to tackle the stairs yet.

I think you could stop the wainscot about where the baby gate is, but at the top of that single step. Use a piece of vertical trim to define the end of the wainscot. I'd bring the trim all the way to the floor, cutting away a bit of the baseboard, like a door jamb. It defines the final arrival upstairs, and deals with that lack of baseboard transition.

Thank you @bpathome for the suggestion, however my oversized piece of artwork is in the middle of the window at the lengthwise hallway wall. So it overlaps a bit where the baseboard ends, hanging the piece of art was a headache trying to get the right placement because of that step transition.

I could hang the artwork in the middle of the wainscoting. It is pretty large, so it'll hang over top the wainscoting which might be weird.

I can't help with the detailing until I know how thick the wainscoting you're proposing is.

Hmm, I'm not entirely sure myself. I guess standard thickness, I don't want to go too crazy, just want to dress it up a little bit. I'll have to go in and take a look at some examples.

It looks really nice the way it is. I wonder if it would really be worth the trouble.

I'll take a look at 3D Wall Panels but the designs seem a bit modern for the style of our house.

Depends on what you like....this might work, or other more subtle designs

Don’t care for the 3D at all. Do you have wainscoting in other areas of the house? I would expect to see it in formal public rooms if it’s in the hallways or stairwells. If your home is a more open plan casual style, with no mill work, it might seem odd to have it just in a hallway. Especially to have it stop halfway. Just a thought. I like your wall color, mind sharing?

@saypoint I don't have any wainscoting elsewhere as of right now but I wanted to started somewhere. If this DIY goes well, then I'd consider doing the main floor.

The wall color is cheap builders paint (cool white). No idea what type or brand, plan to paint over it a grey tone with white wainscoting.

@hoovb Thank you for the example! That's exactly what I was thinking but way above my experience level lol. I might have to consider having a pro do that :)