You can tell when the GPT is writing—delve, bespoke, navigate, etc.
One of the prompt additions you can use to help the language along is to give grammar directions.
Stick this into your favourite prompts for a better, more human result:
"Use the dependency grammar linguistic framework rather than phrase structure grammar to craft a response. The idea is that the closer together each pair of words you’re connecting are, the easier the copy will be to comprehend."
-This is the addition I was talking about during our last Irish Tea Time chat. Also, here is a list of the 50 most common words that an LLM will use, and tell the AI to avoid using them to sound more human. You can add the list manually or as a document.