Facebook Messenger, Duo, SMS and Hangouts are offered by different companies. The reason people are so baffled by Google's messaging apps is that there are six

Facebook Messenger, Duo, SMS and Hangouts are offered by different companies. The reason people are so baffled by Google's messaging apps is that there are six of them from one company, with no coherent explanation as to why. Even if I want to go "all in" on Google services, how do I know what to use?