The apple iOS model seems to be the most promising here. It comes with huge tradeoffs in user control but for a large part of the worlds population I think its the right choice.
But in this case you dont lose any level of control, since the appstore itself there isnt limited. The only thing not allowed is unsecure apps. Thats all.
Yes the iOS idea is great, but there is no need to impose arbitrary restrictions.
As for the PC, i think what Apple was doing with macOS until recently (allowing you to run unsigned software you downloaded from the Internet by doing the "right click dance") was a perfectly fine compromise between security for computer illiterate people and still being in control for people who know what they are doing.
Nothing about Apple's model requires Apple to be the only one who can say what you can do with your own device - you can still have Apple be in control by default but also provide a way to take control yourself if you know what you are doing.