It's a pretty dire situation. There are two major options. iOS is iOS. Android is at least somewhat open and Google free Android actually exists.

The problem is that you often need a smartphone running either Android or iOS to participate in modern life. Unfortunately when running Android many apps that one might be more or less forced to use do not just require AOSP, but expect the presence of the proprietary Google services malware.

If we want to create an independent mobile OS AOSP might actually be a good start. We're just faced with a world that is actively harmful to people having control over their device and data.