How effective is watchdog parental control for managing screen time?

Oh my goodness, screen time! It’s such a worry, isn’t it? My little ones are glued to their tablets sometimes, and I just don’t know if it’s safe. Does Watchdog really protect them from… you know… everything? What if they see something bad? I need to know it’s effective! Has anyone had any problems with it? Is it hard to set up? I’m so nervous about all of this.