It works if you let someone else set the reset email to their own email. That way you can’t just reset. My parents help by setting a password and then setting their email as the reset

I tried it a few weeks ago but found out quickly I can just reset the password so this method isn’t very useful but it’s the only thing iPhone really has.

Go into settings and find a section called “screen time” there you can limit access to websites and apps but it’s not permanent and you can turn it off. The only thing you can do is lock the screen time settings but you would just need someone to make the password so you don’t know it.