Yes, the market exists and there are several competitors. I've looked at https://sunbeamwireless.com https://sunbeamwireless.com, which runs their Android vari

Yes, the market exists and there are several competitors. I've looked at https://sunbeamwireless.com https://sunbeamwireless.com, which runs their Android variant, BasicOS. Haven't purchased yet though. Light Phone is similar. Gabb and Pinwheel sell phones oriented at kids, and both have OSes based on Android. Unfortunately, as you say stock Android as well as iOS don't make effective locks. What they offer is passable for parents managing their kids' phones, although in practice kids often find ways to bypass. It's very difficult for an adult who wants to self-regulate. There are some hacks you can do, like MDM, but it's not at all straightforward. I'm looking to connect with people about this topic. In fact I want a business partner, although I'm also interested in people who just have input.