I would rearrange this as a home office and use the two white chairs as a seating area by the window and put a table between them. I would also swap the middle painting on the wall for a flat screen because HGTV is my inspiration More
Home office: Perhaps the full-wall shelving unit goes on the wall between the new office and current office? Then the window wall is left without built-ins around the window and the adjoining wall is open for artwork. It would look bigger.