thou im not sure that 1GB of <comments on anonymous internet forum> will do less harm than a few hours of vanityfair videos.
Education and setting an example are two others I have in mind for now - the latter is of course easier said than done but honestly, if we truly believe something is healthy, why not do it ourselves?
I allow restricted access to my kid: no mobile phone access, limited time to watch cartoon, no tv, limited access to laptop only for scratch for example, limited access to some educational videos about nature... He can use command line or repl to play for example with math questions... While also getting used with keyboard, mouse... Trying to find a good balance.
But unless I plan to keep him at home he goes to community and socialize and I have to explain why we don't do this or why we don't do that and to explain why others are playing games or have phones. And I do explain.
But I am also concerned about the social groups they are all growing. The majority are not like this. So he will live in a society maybe with people hooked on screens. Maybe he will find a bubble maybe not.
Data allowance. Not just mobile data, Wi-Fi as well.
You can blow through 1GB of TikTok in an evening, but the same 1GB gives you more text than you can consume within a month.
Gradually increase it the same way you would with money.