There is a lot missing here. Without paying £30 I cannot see what the adjustments in the adjusted models are.

There is no breakdown for different ages. Its very likely that the effect on a one year old and an eight year old would be very different.

There is no breakdown of what they are watching.

A whole of of confounding variables. Screen time is inevitably going to be associated with less adult attention which is known to be a major factor in development. Lots of others.