That is my experience, it's generally quite decent for small and simple stuff (as I said, distillation of documentation). I use it for rust, where I am sure the training material was much smaller than other languages. It's not a matter a prompting though, it's not my prompt that makes it hallucinate functions that don't exist in libraries or make it write code that doesn't compile, it's a feature of the technology itself.

GPTs are statistical text generators after all, they don't "understand" the problem.