Don't put the devices in their hands until they're older. And even when you do, immediately limit the time from the start. As an IT guy too, it's how I'm doing it. Use an older device without any accounts setup on it. Install fdroid and only get apps from there. Leave it on airplane mode except when wifi is needed (by you).

At this point, my 4yr old gets bored rather quickly with my old phone.

I have a 4 year with unlimited access to her tablet. She will throw it down in a second to go to the park or play with friends. Or just because I told her to put it down.

I gave it to her at 2. I think the key for me is disallowing it in combination with anything else. She can't hang out with me and play on her tablet. She can't play in the park and use her tablet. I also keep her in Amazon's walled garden for now. I've decided that Amazon's opinion about what's good for kids is better than most others. I've also been encouraging my daughter to use it as a learning tool like she'll have to as an adult. She's used to to trying to learn Spanish when she got a friend who spoke it and to reinforce what she's learning in preschool.

All in all, I think that technology is mostly about boundaries. My nephews are addicts but mostly because they have no boundaries. My sister overruled me over having a "digital detox" day after her son had been playing videogames non-stop for 3 days now. Kid watch some YouTube or something. Nope apparently it's summer so he can do whatever. This will definitely not be a problem when school starts 🙄.

Any kid who is desperate enough to leave the house for wifi was failed years ago about boundaries and healthy usage. Their parents are silly anyway. Parental controls can make a literal any device a brick. This is the first lesson I taught my kid. Tablets work at my pleasure. My daughter doesn't even whine about it anymore. Tablet becomes a brick at 8pm sharp and she just plugs it up and gets into bed.