For the time limits you could take a look at Circle, which allows you reasonable control (at an individual level) of when and how long your children are using N

For the time limits you could take a look at Circle, which allows you reasonable control (at an individual level) of when and how long your children are using Netflix etc. And offers some control of what (by classified type) or domain whitelist/blacklist. Don’t think I can block specific urls so can’t achieve whitelist only YouTube.