China actually already has a system in place that kinda works for their existing video game restrictions - your accounts are connected to your social ID, or to a social media which in turn is connected to your social ID. Alternatively I wouldn’t be surprised if like what they do is connect your SIM card to your national number (which is possible - some countries do it for 2FA for government stuff and banking) which is what they use to control internet usage
…of course it does little against the tried and true method of “using your mum’s phone/ID for games”