How can you prove a negative? That is 1000% ridiculous.
You have a bunch of apps internal to your phone. They all talk to each other, so they can provide the features you want, or may want sometime, to use. They don’t talk to anyone or anything outside your phone. Where is the security issue here?
If you truly believe it is somehow a security problem then get rid of your iPhone. And don’t get an Android; apps on an Android also share internal data.
Your only option is to get a dumb flip phone, and never use any smartphone or computer again. All computers share internal data between apps also. Of course, flip phones also share a lot of data with the cellular network, so that isn’t an option, either. Give up all mobile phones, and get a hard-wired copper connected dial phone. If you can find a carrier who will still install copper.