Probably rust for the later these days

Python is slow often 1% of the speed of a fully parallelized and vectorized C app compiled specifically for your architecture. There are ways to improve speed like libraries, PyPy, numba, etc of course but often theٌse are application specific and do not always give the performance you might think. I love Python, but for speed it is not the best.

There are many easy-to-learn languages, and others actually have useful software development ideas (immutable by default, for example). I understand if expectations are lower, though, from the language talk, and if any language with the required libraries is fine.

What language features do users say helped them? Existence of libraries didn't make C a good language

Hm, except in the way that being able to call into library functions "relatively easily" from the base language was a good way for others to create a bajillion handy libraries.

And once you've got those available to extend your language in any direction you want, you're well on your way to ubiquitousness.

I used Lua as a scripting language directly tied to C. It is useful for allowing scripts to interact directly with compiled code. The compiled code is still the focus, but the scripts allow changes without a recompile.

I used to like C#, but dotnet didn't become as portable as I hoped it would.

I use C (embedded), C++ (everything), Python (data manipulation), PowerShell (pipelines) and bash (pipelines).

I hope you can find a non-homework job to use whatever skillset you are developing.