When shutting down the Mac the first time, it will prompt you if you want to open the same apps that were open at that time. If you elected to do so, that is why they will appear each time you start up your Mac.
To stop them from opening at login, first close each app that is running. Use "Force Close" if needed for any "resistant" app. Then shutdown. Again, you should see the option to open apps at startup. Be sure to deselect that option.
Ref: https://support.apple.com/guide/mac-help/open-items-automatically-when-you-log-in-mh15189/mac