Suggestions from neutral colours: https://www.dulux.com.au/colour/colour-trends/2018/essential Ceiling & walls the same colour is a good choice for square set. There will be subtle hue difference in various lighting situations anyway, which provides depth and makes for an interesting look.

you could look at staining this one>? Bamboo Woven Ply - Bamboo Australia | Sunshine Coast or may I suggest a good detail joiner could make it to your custom panel sizing and finish it suitably for the kitchen splashbacks (if that is what it is for>?) I can suggest someone who would be able to custom make this if you wish.

I'd say a charcoal -- you don't want anything too white or grey IMO , or it will be overpowering in an underwhelming way , and most other tones either clash or will look cold , or both .

Since the tv is black and dominates the room, I would choose black frames. I would start with a large artwork on the corner near the red thing in your photo. Black will stand out on the walls. And a large tall plant in the other corner. With a small black framed artwork. Can you position a clock on the wall to the left of the television. Then it can be seen while you are on the sofas. Assuming the dining room is adjacent to the lounge room, it can also been seen from there. I would go for a black frame large interesting textured clock.