In real life it is inconceivable that you would simply let your children go everywhere unobserved, often on the internet. Because even if you set a screen time, in the allowed hour there are no hurdles for your child on the net and as everyone knows, everything can be found there.
A first step is therefore that you specifically select the apps that your child is allowed to use. It is best to do this with the child. Surely it will come up to you from time to time and say that everyone else can use a certain app. Take a look at the app yourself and discuss its use with your child.
Once you have reached an agreement, the app can be installed and used. If not, everyone else uses the app, but not your child. It is particularly important that you explain the decision to your child and not just issue a ban.