Turn it into an archway and no trim needed.

That is a major miss in the design. From the pic, the doorway seems wide enough that you could build out the sides, and do new jamb with the proper sized casing.

ETA: The picture is too far away to tell, but is there room around the window for trim? They should match.

You could do something like this. (Not to scale). Since you have no room on the kitchen side you could case it like an archway on one side with an eased edge, and on the Living Room side use casing in the conventional way. As long as it's done thoughtfully It would work, especially since there is paneling on the kitchen side.

No applied trim.  Instead add a jamb with spacing to create the effect in this picture. Clean, simple detail

Id frame in the doorway to make it smaller so you can add trim

Thank you all! Lots of great ideas to work with here. I appreciate it.

I’d add a wooden jamb painted white and no trim. Great looking space!