I would really like to know how an application can get installed without any user intervention. The user has to be able to tap on something to install, isn't it?
I see these reports[0] saying - > the same sophisticated hacking technique – known as a “zero-click”
[0] https://www.reuters.com/technology/exclusive-iphone-flaw-exploited-by-second-israeli-spy-firm-sources-2022-02-03/