Apple screen time parental Controls were created because third party software was using MDM which Apple didn’t like. If Apple can lock down a phone with mdm for companies to give to their employees why exactly do you think software built into the OS is easy to get around like net nanny?

Googling found an article about getting around it.

Nothing on there an 8 year old would do and there’s directions on how to prevent any of it. You can lock down changing system settings or even stop them from editing their contacts.