No matter what I tried, I could not get youtube to be blocked on a PC running Windows and using Google Chrome Browser with Deco S4.   tried ensuring that MAC address was not set to random as suggested in the FAQ below.  The blocking works as expected on Microsoft Edge and Internet explorer browsers.  It seems like Google has a way of allowing access to their sites that somehow bypasses the parental controls?  Anyone else have this issue?  

https://www.tp-link.com/us/support/faq/1598/

Note: Please make sure the Private MAC Address is disabled on your clients, otherwise, the parental control won't take effect.