Even best in class LLMs like GPT5 or Sonnet 4.5 do noticeably worse in languages like C# which are pretty mainstream, but not on the level of Typescript and Python - to the degree that I don't think they are reliably able to output production level code without a crazy level of oversight.

And this is for generic backend stuff, like a CRUD server with a Rest API, the same thing with an Express/Node backend works no trouble.