[cookiengineer]

Get an OpenWRT router, block roblox on a network level.

Don't share the admin password with the child.

a) addiction leads to child learning about network technologies, pentesting, and how to bypass the router firewall

b) child stops playing

I think both options are a desirable outcome.

And if a) happens there's a lot of possibilities how to make it harder. Install family management software that limits internet time. Install an antivirus tool that blocks roblox binaries. Install an EDR that blocks roblox binaries. Install an exchange server to remove admin capabilities from the local user. Install their smart phones as an enterprise-managed device with MobileIron where they cannot install anything. Etc. pp.

Each level will force them to learn more about how computers work and before you know it they'll learn about programming and cyber security as well :)

My point being that real life is too boring. So make it a game that's a rewarding challenge.