I can't say this is what you should learn, but what I've been learning recently and enjoying:
1. Ionic Framework with React/Typescript (https://ionicframework.com/blog/announcing-ionic-react/). I've never done much frontend work or mobile development before, but it's a lot of fun. Ionic makes it easy to make a PWA and access native device functions. Typescript is one of the nicest languages I've coded in - the type inference is wonderful and the linters catch a ton of mistakes I wouldn't have otherwise.
2. Flask + Python. Really enjoy the simplicity of Python. I've been getting into type annotations with MyPy. I honestly have mixed feelings about Python - for small projects/exploring data it's been fantastic, but I feel really limited by the lack of type safety when things get bigger. I've also been playing with some BDD frameworks (behave and pytest-bdd), since I really want to get a better understanding of how to build effective testing infrastructure.
Python has grown on me a lot, and it's now my go to language if I need to test out a concept. If I have an idea for a relatively small project (few days maximum development time), then Python is my clear winner (unless performance is essential). After it's made, if I see room for improvement, I go right to a more performant language. Recently, Python rough draft -> Rust final draft has been a great workflow for myself.
1. Ionic Framework with React/Typescript (https://ionicframework.com/blog/announcing-ionic-react/). I've never done much frontend work or mobile development before, but it's a lot of fun. Ionic makes it easy to make a PWA and access native device functions. Typescript is one of the nicest languages I've coded in - the type inference is wonderful and the linters catch a ton of mistakes I wouldn't have otherwise.
2. Flask + Python. Really enjoy the simplicity of Python. I've been getting into type annotations with MyPy. I honestly have mixed feelings about Python - for small projects/exploring data it's been fantastic, but I feel really limited by the lack of type safety when things get bigger. I've also been playing with some BDD frameworks (behave and pytest-bdd), since I really want to get a better understanding of how to build effective testing infrastructure.