As much as I love Google (not even a little, my love for that company is negative and becoming more negative per second) I would love to run far far away from it. Here’s another ball and chain I need to break.
Where can I find a simple parental control access system for my phone and or computer that I allow my kids to use?
Its Android
if you want to lock your phone to one app when you hand it to them you can use app pinning in settings. otherwise look into creating a user profile and see what you can do to lock that down.