Screen time for us was playing games with an educational value and watching TV with at least some educational value.
Recently we've started letting the five year old watch TV purely for entertainment, and the three year old sometimes watches too, but even then, both of them suddenly got a lot better at storytelling and coming up with their own original stories.
So even "pure entertainment" seems to have educational value for the kids.
The rule in our house is that you can't use a screen if the sun is up unless it's a weekend. That seems to be a good balance (although under the current conditions that's flexible if the screen is for an online class).