You can't divide things up. If you want one large room you will not have a kitchen and living room anymore but a kitchen with living space. This is a bad design and a good way to keep homeowner spending money to remodel Once everyone does it the trend will be to bring back separate rooms. Here is some info about the open floor plan. 11 Reasons Against an Open Floor Plan

Not stupid. Picking paint colors is always hard, and some rooms are just particularly challenging. I've seen a lot of rooms on this board, and believe me that your room qualifies as particularly challenging. Before you tackle paint, you should improve your lighting, since it can make all the difference in choosing colors. The room IS dark (look at the difference between your photos and the realtor's professionally lit photos!), and if you aren't getting light from outside, you need to compensate with more, better interior light. I don't see any floor or table lamps in your furnishings; that's one place to start. Are the foyer pendant, ceiling fan, and dining fixture the only ceiling lights in the room? Any recessed cans? I would start with brighter LEDs in all the ceiling fixtures, and maybe tweak the color temperature (though I think your problem is more that you don't have enough lumens than about color temperature). Can you address the carpet on the stairs without tackling the carpet in the upstairs? I was just looking at DIY stair carpet removal and refresh with paint. It's a lot of work. (https://www.remodelaholic.com/under-100-carpeted-stair-to-wooden-tread-makeover-diy/). I wouldn't paint the wood trim. My sympathies on your divorce. Regardless of the circumstances, the process is difficult and disruptive and expensive.

We will be using Benjamin Moore Paint

A Farrow & Ball colorist suggested FB Bone for my N facing LR with FB Skimming Stone ceiling. I had them both color matched to Benjamin Moore paints. Look at BM October Mist. It is their color for 2022