One thing I'd like to respectfully point out to our community, which I personally think is going to snowball into a full blown health crisis, is children's posture while using tech. I live in NYC and everywhere I go I'm seeing kids and adults craning their necks and backs at 45-60 degree angles. My mother was a seamstress for 30+ years and the consequences are horrible. Keep an eye on it
As for my strategies to manage this, I nag frequently (and my kids know the consequences are losing access). For the few times I do give them screen time on the go, I force them to watch with the phone on the table and either leaning on sometime or in this little phone holder that forces them to sit upright to see the screen.
Here is a random link that quantifies the impact on weight on neck at different angles: https://healthmatters.nyp.org/how-to-prevent-tech-neck/