How do I stop Apple News from opening when I start my MacBook Pro?

I tend to have a different take on this.

Message ( Apple Message ) Application does not appear on any of the 3 Apple Computer running Ventura 13.3.1

It has never been set to Startup from Login Items on any of the 3 machines including a Brand New M2 MBA with 13.3.1

Go figure

Two places to start this

1 - Check in System Setting and see what is set to Launch when the computer is first turned ON

1st image below

2 - When the computer is shutdown are the offending application still active

If Yes, refer to 2nd image and Un-Check the " Reopen Windows when logging back In "

When the computer is shutdown, is Messenger application still active even if Not Appearing on the Screen ?

If Yes, refer to image below and Un-Check the " Reopen Windows when logging back In "

You are welcome 👍

Problem solved

Messenger is not in the login items yet starts automatically

If you mean, "Messages", It is actually listed in startup under Login Items. Unless it was removed by the user.

It is FB Messenger that starts automatically and it is not in Login Items

As this is a Third Party Application, suggest communicating with the Developer of this application for assistance