You need art + one v large piece or 3 in a row or a group of 4 or lots of different sizes with ones at the top all at the same height. If originals are beyond your budget buy prints and use IKEA frames. This pic shows four 10 inch prints of my work framed in white in a client's house. Have a look at my profile and of you like my work I would be happy to advise on size and framing options to suit your wall. If you don't like my work then no problem!

I would just paint up to dado height. The 2nd photo has dado rails which you don’t need but just showing you the radiator painted and taking it up the stairs. I’d also paint the skirting boards and you want to paint around 1/3 of the wall height. I’ve used Little Greene intelligent eggshell which would be fine for dirty paws (oil can be a little stubborn) but think I will be trying Sarah’s Mylands recommendation next given how Matt it is.

If the room is not too dark, you could try a grey similar to the wallpaper. However if the room is dark it may look a little grim. Ammonite by F&B or Polished Pebble by Dulux May work, depending on the light. You can then use an accent colour such as mustard yellow or pink in the bedding, throw and cushions.

I would wallpaper that wall to "separate" the dining room and the lounge. I would have a big picture frame on that .