As far as kids and phones, just don't do it. When my youngest was 5 he woke me one Sat. morning at 5am by reciting all the cartoons he was going to watch that day. He had memorized the schedules of several different networks from 5:30 am into the early afternoon, and planned his day.
I had the cable company shut it down. He was clearly very capable of learning and was using that capability learning about cartoons - propaganda. My kids were furious with me then. LOL
Soon, however, they were reading books, because they wanted to entertain their minds. Reading is much different in it's effects on our brains than watching TV, and now that my kids are grown professionals, they are grateful - and recognize that I made sacrifices they respect so that they would be the men they are today.
If you notice your kids being too attentive to their phones, cut the service. They will be better for it, even if they hate you for a while.
It's called parenting, not sucking up.
My mother always said that children need parents, not a couple more friends. It's hard to actually think about how you want to parent when there are so many outside pressures telling you that you are doing it all wrong but above all, it's essential to actually parent. Sounds like you're the kind of parent I'd be glad to have too.