How to stop random apps opening when powering on my Mac?

You need to make two changes to stop the OS from trying to behave like an iPad or iPhone.

Open the System Preferences (System Settings in Ventura). Under the General settings, make sure the check boxes are on for both of these choices:

Ask to keep changes when closing documents

Close windows when quitting an application

The second step is the choose Restart or Shut Down from the Apple menu. In the popup that appears, uncheck the box for, Reopen windows when logging back in.

You can click Cancel after unchecking the box. The OS will still remember your choice.

Now when you startup or restart your Mac, it will not launch any apps that were previously open when you shut down or restarted.

If Chrome is still launching after this, then that would very likely be because it's listed as one of the Login Items under your account name in System Preferences/Settings.

One by one, I turned off the Chrome extensions and I’ve found out that in my case it was a Norton extension (Norton Safe Web) that was causing the problem.

I kept it off and Chrome didn't reappear in the Ventura’s Login Items list anymore.

If you install Google on your Mac, it then becomes an information-harvesting and -uploading "bot" for Google.

If you do not want it to do that, then then solution is to uninstall Google.

Is Chrome listed if you go to System Preferences > Users & Groups > your user > Login Items?