My DDs seem to spend less time than most on screens.
We ban devices in the bedrooms after 9pm, that is our only "measure" taken.
BUT... What are the alternatives in your house?
I have 2 DDs - one an air cadet, the other a St John's cadet - they do those activities 3 times a week, usually including one weekend day,
they both study a musical instrument - and have for years - that requires daily practise,
we see their gran once a week for 5 or so hours (the kids - and we - are polite enough to know you don't spend all of those hours on a phone.),
and finally we are family members of a local gym and go swimming there twice a week, and play table tennis every other weekend.
The people I know whose kids spend a lot of time on screens, ALSO spend a lot of time on screens themselves, sitting watching telly of an evening whilst telling the kids to get off their phone seems odd to me.