Need advice on 12yo wanting a gaming PC

My son has been saving his allowance for 8 months to build a gaming PC. Part of me thinks it's great he's motivated and learning about computers, but I'm worried about screen time and what games he'll be playing. He says all his friends have one. How do you guys handle this? Do you set strict time limits or let them manage it? Also any recommendations on parental controls that don't make them feel like you're spying?