> How do you ensure your kids aren’t skirting any blocks you put in place, looking things up with their friends, getting access to a VPN, etc.?

I don't, because I don't need to.

I had unrestricted access to internet when I was my kids age and I turned out just fine, just like the extreme majority of my generation.

I know that serious discussions about important topics are enough to make sure that even if my kids do access content that's not meant for children, they're not negatively affected by them, just like I wasn't.