I might paint the kitchen, but, it looks fine in the living room, and it also looks like your couch and rugs etc are all chosen to go with the gray. If you repaint, you may have a lot of things, that will no longer look good. A color to go with your kitchen cabinets, is something in the blues, or greens or aqua shades (light colors) Your counters and back splashes, dont really go with the gray walls in the kitchen, however, the blues, greens or aqua shades will go well with everything in your kitchen, except maybe the bar stools.

I don't think Agreeable Gray is too brown next to Rainwashed; I was going to suggest Accessible Beige, which is actually a little bit browner. Since your current colors are all over the color wheel, I think anything you pick will work better with some and worse with others, but I don't think Agreeable or Accessible would look really bad with any of them.

Pictures please

IMO paint the trim there is nothing special about it and it does not work with the floors and then just white walls to work with the art BTW I love that you got the art first and want to enhance it. I totally agree art you love will always work in your space.BUT before doing one more thing fix your lighting , every bulb should be LED 4000K to mimic daylight and it will help a lot when choosing anything else.BTW that pillow does not work with that art IMO to much like you tried to make it work. We have quite a large collection of art and I find our very pale gray walls work well and in our case better than a pure white I used Vancouver Day C2 and a bit darker shade in the bedroom . We tend to like the art to be the star .