There are sibling threads that provide some valuable context as to who might actually need this degree of paranoia. Without that context, this feels like a prequel to a story like this https://www.newyorker.com/magazine/2019/05/06/my-childhood-i....
I feel worse for the kids whose parents don't care and have all their information collected before they're old enough to know better. They're handing children chromebooks and letting google collect their kid's test scores so they can sort children into 'smart' and 'dumb' buckets before they're out of primary school, letting youtube and tiktok babysit them the way previous generations did with television, making them carry cell phones at younger and younger ages etc.
I think there's some solid middle ground there, but those kids will be much better off having been made aware of the issues and having their information at least somewhat protected.
The Samsung keyboard that shipped with my cell phone was sending every single letter I typed to a third party whose privacy policy said explicitly they used that data for market research and to make determinations about the intelligence and level of education of the user. Companies are collecting analytics and monitoring people while they play video games which is then being used to group them into categories.
Lists of people with low intelligence, poor education, alzheimer’s or dementia are extremely valuable and data brokers are happy to sell them to advertisers and scammers. Google just put themselves in a position to collect that kind of data as early as possible. Why would you expect them not to use it?
Kids can be educated about the dangers of data collection, be mindful about the data they are giving companies and aware of how ways that data will be used against them so that they can make smarter choices without cutting themselves off from the world they have to navigate and be a part of.