Facebook Messenger has grown from a niche method of contacting someone you didn't know very well into the main method 1.2 billion of us use to communicate with our friends on our smartphones. Unfortunately, Facebook has bogged Messenger down more and more over the years, adding more unwanted features, reminders, and general bloat that eat up your phone's resources and battery life. It turns out that Facebook has long-released an spin-off app called "Messenger Lite", designed for markets where users' phones might not be able to frivolously eat up gigabytes of data or spare RAM and CPU cycles on games and features copied from Snapchat. The catch is that it's probably not available in your country.
However, if you live in North America or elsewhere and you can't find the app in the Google Play Store, there is another way to get Messenger Lite. APK Mirror, a trustworthy site that mirrors install files for Android apps, has the Messenger Lite file up for download here. All you have to do before installing is turn on the ability to run downloaded APK files in the "Security" menu by turning on the "Unknown sources" option. You should find that Messenger Lite, while lacking some features such as "chat heads" or voice calling, is incredibly responsive and refreshingly simple
If you would also like to try an alternative to the Facebook app itself on your Android phone, "Friendly" is a good option.