How to completely remove Siri and related data from iPhone 16e?

No.

1. Siri is not an App, so there is no app to remove.
2. Siri is built into the OS is an inextricable part of the OS and cannot be removed, you can turn it off in settings, but you cannot remove its components from the OS.
3. Settings ➜ Apple Intelligence & Siri ➜
   1. Apple Intelligence turn it off
   2. Talk & Type to Siri, set it to off
   3. Allow Siri when locked, set it to off.

We’re unable to delete Siri from our devices.

If you’re wanting to disable Siri, check out the steps under Phil0124’s comment ❤️

jmaussie20 wrote:

How can i delete Siri and all siri related apps/data from iphone 16e?

Perhaps if you explain why you're asking this, people can give you some alternate suggestions.