Nowadays developers tends to learn a framework and not the language. It's important to know the pros an cons of the languages and know what fits in your needs.
What is the purpose of your backend applications? it's a web based app, need horizontal grow? multithreading? work with queues? multiple processes? a lot of security? need to be super fast?
This this are interesting to consider, and when you know exactly what you want, go for the best language that fits, and then with one of the frameworks for your needs.