Create a mini app (with tasker if necessary) that has a 10 second delay before it shows an option to launch/open whatsapp.
Include this app in the productivity lock so that it is not openable outside intended times. (And neither is a preview of whatsapp due to the 10 second delay.)
Hide the whatsapp app icon from the list of apps so it can only be opened through this ("new") delay app.
Create a mini app (with tasker if necessary) that has a 10 second delay before it shows an option to launch/open whatsapp.
Include this app in the productivity lock so that it is not openable outside intended times. (And neither is a preview of whatsapp due to the 10 second delay.)
Hide the whatsapp app icon from the list of apps so it can only be opened through this ("new") delay app.