You are going to have to consult a structural engineer before going any further. They will tell you what and if there are any options here.

I would do exactly as rocketjcat illustrated. You could even turn it into a bar since it separates the living and dining room. Lock it if you have little ones.

I agree about puting some cabinetry between them to better define the space.

Also - the white columns are clashing in terms of both color and style with the stairs. The stairs are MUCH more casual.

Reshaping the columns and making them square/rectangular would help (and this is probably necessary to build in cabinetry between them), as would painting everything but the stair treads and the railing white (all parts except where your hands and feet touch).

Don't know what you budget is, but columns in a room with wall to wall carpeting strike me as a little off. If possible, I would replace the carpeting with hardwood.

My priorities would be 1. Paint stairs, 2. Replace carpet with hardwood, 3. Reshape columns and get built in cabinets.

But I can easily imagine a scenario where it makes sense to skip replacing the carpeting,

I've seen columns like that on HGTV and people put square boxes around them to make them look more contemporary.

Easy one. Do a lower Cabinet ( like in the photo from your one adviser ) to act as a server or Bar counter, but then tie it all together with a Valence. Great aesthetic, still open and additional storage.

Cabinet idea seems neat. If you're not up for that, then just try to arrange your furniture so that some pieces abut the pillars, so that they aren't an additional obstacle to walk around. (Previous owners did that with one couch but not the other.)

How do you know they are structural? Have you seen a drawing that indicates that? You could remove the cladding and see if there are posts beneath. If they are structural, then I agree with the other posts to incorporate them into some sort of cabinet or credenza.

I haven't seen the original drawings but my neighbors have the same beams in their living room, which was installed by the builder. I'll definitely verify that before taking any actions. I'm planning as if it is a structural beam.