IMO you're right that "prompt engineering" is a cringe-y term because it implies what you're doing is mostly writing prompts. That being said, I don't think that's what it actually entails, any more than "backend engineering" is mostly writing SQL queries. Prompt engineering is building the systems around the prompts e.g. writing the LangChain or whatever code, parsing stuff and interacting with structured DBs, message queues, etc (and occasionally writing prompts too, but that's a relatively smaller part). It requires some domain-specific knowledge e.g. chain of thought and retrieval augmented generation techniques, some basic linear algebra, keeping up to date with new models and new ways of running them (ggml? gptq? openai functions vs logit masking llama 2?), but it's more or less backend engineering with a twist.

I've seen some of the more serious people switch to the term "Applied AI" which I think encompasses the role a lot better. Also I've seen a decent number of grifter types saying they're "prompt engineers" when what they mean is they're writing prompts into ChatGPT's UI, which I think is part of what drives the cringing feeling when you hear the phrase "prompt engineer" and probably drives some of the movement away from the term for engineers.