As I said shady apps are/were also in App Store. Today they are not able to manually really review and detect all malicious apps. MacOS is still more open and the world didn't collapse. At minimum they could provide similar mechanism like MacOS but on iOS.

1) apps still notarised so if app later detected to be malicious it can be remotely uninstalled

2) if it's you grandma/grandpa phone - allow to setup iphone as more limited parental control that only other from family can install apps

3) do automatic apps scanning before installation to detect app is malicious - revoke developer certificate in this case or ask them for clarification