#sims 4 help requested

I recently posted on the Sims 4 Studio forums but didn’t receive any response.

I decided to revisit my Glamper set and see if it needed any fixes. The biggest issue that has always bothered me is that the custom walls are darker than the camper ends (even though the textures are the exact same color).

Even if I make them “shinier” they are still dark, just dark and shiny (I removed the shine like a year ago which was an improvement). I can’t figure out how to lighten them up. I’m assuming it has something to do with shadows and the way light hits the walls but I don’t know how to fix it.

This has always bothered me and I would love tips if anyone knows how to fix it! Please help!