thrown into a backend project as a backend dev with a language I don't know, how fucked am I?
The title itself is a recipe for disaster. Also this is a semi rant.
Yesterday I was informed that I will have the honour to implement the core functionality - which is an interface layer to use the driver of a very expensive hardware shit - of the software I’ve been working on as a frontend dev.
There are two possibilities for the language: C++ or C#. The one that was proposed/imposed is C#, which I know nothing of, while at least I have some hobbyist experience with C++; when asked if I could take some time to familiarise myself with C# I was basically laughed in the face, saying I will learn on the field and at least some of them have some experience with it.
Should I insist to go with C++, or is that an even worse idea in an already fucked up situation?
C++ is a worse idea, it is not a good web backend language.
C# is pretty easy. As long as your boss doesn't expect you to magically already be good at the thing they refused to allocate time for you to train in, you probably can just start trying to glue bits of C# web API examples together as your first project.
It’s not web backend
Oh sorry, I saw "frontend dev" and assumed that meant web and not like local application.
If you are doing something less popular involving non-web messaging between processes that might be harder to break into.