I thought I was going to end up with one giant beige box too, but it didn't happen. I checked https://costacover.com/collections/beige-wallpaper picked a slightly different shade with some texture instead of matching the furniture exactly. That little bit of contrast made a huge difference. I threw in some dark wood and black metal details and the room suddenly had way more depth. So yeah, beige on beige can work if you don't make every single thing the exact same color.