I think any trim work would compete with the mirrored wall that you now have. Instead, I would add a large piece of art to the wall in the dining room area to reference this as a different space.

Geez, no molding. Select art for the wall and divide the two areas by using a potted trees.

You could even put a buffet in the dining area under art.

Where would you stop? It just won't look right. Maybe a beefier crown/floor molding would give you more interest on that side of the room? Given the width of the mirrors I think the room could handle it.

I would not add any more decorative trim

It suddenly seems everyday on houzz at least one person want to put random molding or trim on their walls in places that don't make sense and are just an add on rather than a feature that runs throughout the house.

Artowrk, a plant, appropriate sized furnishings usually seem to be the appropriate cure.

Thank you! I am glad I asked! Any artwork suggestions?

This comes from design media, (Houzz, HGTV, Pinterest, Instagram) where wall features are added for a variety of reasons. On HGTV they are added to renovations because they are relatively inexpensive, eye catching, but completely impersonal unlike art, so they appeal broadly to potential buyers of flips, for example. On Pinterest or Instagram these things are done, because again, they are easy, eye catching, inexpensive, and again, really impersonal, unlike taste in artwork, so they can be presented as vignettes and get a lot of clicks and likes.

The problem with PInterest and Instagram and such is that they are often without any context of any sort with regards to the rest of the room or house. I know an influencer who creates stuff over and over in one isolated corner of a room, that has nothing to do with anything else in the apartment. It's like a little stage set.

So people see these, the pictures are kind of fun, and then they want to do them.

A much earlier phenomenon was the "Puddled drapes" thing in the early 2000s on Trading Spaces and such. These weren't real "puddled drapes" these were off the shelf curtain panels that they didn't have time to hem. and better too long than highwater, so they called them puddled drapes, and then everyone was doing it for a while.

You'll need a large piece so check greatbigcanvas.com.

They often offer a discount on the first order.

These three abstracts from greatbigcanvas.com appeal to me.

I like the last one - where can I find it? What size is it?

Thanks!