If those pocket PCs had useful and creative apps only and maybe some non-addiction-optimized games they’d be fine. The problem is the apps, not the hardware.
With kids the absolute worst seem to be YouTube, TikTok, and Roblox. All three are banned in our house. The kids have their own devices (with monitoring) and can play games and explore other stuff but we do everything we can to keep addiction systems away. It works fine. Our kids engage with real people when they are available and tend only to go to the screens when bored.
We don’t have a hard time limit but if we notice too much screen time we set up play dates or book activities. They’ll go for those things over screens… or at least they do now that the worst stuff is gone.
Banning YouTube was the single highest impact one. The whole mood of the family and home noticeably changed. We got our kids back. They liked their friends again. To this day my #1 piece of parenting advice is to ban YouTube. A few others too but that one seems the worst for some reason.
Engagement maximizing algorithms and UI dark patterns work incredibly well to the point that they can behave like a drug.