I found it such a hassle to keep locked down I gave up. Like, he'd be so aware that he'd find ways to watch me enter the PIN code when adjusting the settings. I'd have to be ever-vigilant and I got tired of it.

I've concluded the only way to avoid workarounds it to reduce my own screen time. I stopped having a tablet myself. Got off the Iphone too.

I still need some smartphone for work. Got the smallest one possible so at least games aren't really fun.

Try discipline