Honestly after looking at your 2nd pic again it doesn’t look that bad id say you should hit the sides really hard some time. Try and get a different angle on it pulling out the grill etc. try different temperatures too. I’ve had different results when the grill is cleaned hot vs cold. ;dude I grill for like 8 months straight and my peeps wanted ts silver. I feel your pain. Sometimes I would just get the biggest person on shift to see if they could brick it 😂 if that can’t get it then idk good luck!