Gaming is out of control

My 12 year old is gaming like 5-6 hours a day on weekends. He wakes up and immediately gets on his Switch or Xbox. We set a 2 hour limit but he just sneaks it after bedtime with headphones. His grades haven't slipped yet but I'm worried about his eyes and his social life. He'd rather game than hang with his friends in person. How do other parents handle this without constant fighting?