1st is a NetGear router with parental controls. It helps a lot, but is not perfect. It controls things at the internet level. IE, it won't stop them from playing games on their phone, or watching or listening to videos/music that is already on their phone.

2nd is a subscription app called Qustodio. Again, it helps a lot, but not perfect. This helps both with internet blocks and phone/device app logging/blocking.

The third thing we use is Google Family link. It's functionality is similar to Qustodio.