Sorry, not clear on what the top photo is. Is that your living space upstairs or a reference photo of a style you like? What does the rest of your home look like? How is the trim treated there?

At minimum, I'd match the crown and baseboard that you have upstairs. And I might also trim out the support posts with painted millwork. If this is a more casual space in an otherwise traditional home, the wainscot you show in the top photo would work. I'd also consider beadboard or a Shaker style panel. Some ideas:

What? You need to supply a lot more detail.

Sorry I didn’t supply enough information.
The finished photo is a reference for a wainscoting.
We do not have any crown upstairs but we want to add it. We have 10’ ceilings on the main floor.
My home is traditional.
Hope that helps a little.
Thank you

Here is a photo of the outside and another of a trim style I like.
How do I decide on the correct size of crown and baseboard?
Does it need to match what’s on the main level?

No it does not need to match the upstairs.

But it looks nicer if the up and down stair areas look related in style and detail.

Related style moldings but not necessarily the same size as upstairs. The tan hallway needs some trim. Your beautiful, traditional home requires trim in almost every room.