Setting up an old iPhone 13 Pro for use as a camera

Wendymh wrote:

adding in that I have a dive case - I neglected to mention that - so I’m not destroying anything:) I have dove with it before.

OK. Your original question was if you delete apps from the phone, will it affect your new phone. And then answer is no, it will not do anything to your new phone. But if you sync data with iCloud on your iPhone, which you also sync with your new phone, removing photos, messages, notes, etc., from iCloud will also remove them from the new phone assuming they are both using the same Apple Account.

There is a base set of Apple apps that cannot be uninstalled due to iOS integration. However, you can use the steps in this Apple article to hide those and delete others:

Remove or delete apps from iPhone - Apple Support

To add, I am not comfortable with the idea of a working iPhone becoming an iFlood either.

So you have an old iPhone you'd like to destroy? You can't swim or dive with an iPhone. There are bags you can buy, which suggest they're waterproof. But we see posts all the time here from people who used a bag and water got in and destroyed their phone. Pressure is another issue.

This doesn't really answer your question, but diving with an iPhone is just a REALLY BAD idea.