If you're keeping up with the various state management techniques in Flutter, you're probably aware of the recent combination of Cubit into the Flutter Bloc package. Whether you're a Bloc user currently, or if you've considered Bloc in the past but found the boilerplate code overwhelming, this video tutorial by Matt Rešetár of the Reso Coder YouTube channel should help bring you up to speed on the changes, and help you decide if the new combined package is worth a fresh look for your own development work.
Although I will confess to violating this principle myself, localization is something best considered at the beginning of a project, rather than after you have dozens of hard-coded strings sprinkled throughout your code. :-)
This very in-depth tutorial by Edson Bueno sheds light on the difference between internationalization and localization, along with some solid practices for helping your apps reach your customers in their own languages.