There is Android support for locking things down for kids, but I do not know how effective it is - mine are adults of close to being an adult now.
Its also hard to do without. I would have to pay a lot more for my daughter's bus tickets to get to school if she did not use the bus company app (because that would mean daily tickets instead of monthly which are a lot cheaper). Its where a lot of kids not only discuss things and social, but organise things (although I encourage doing that at a desktop rather than a phone when possible) so kids without get left out.
It is not just sad, it is harmful. "What is life if full of care, we have no time to stand and stare". It is the opposite of mindfulness.