The thing is even setting aside the potential academic misconduct details - generative AI tools are basically just statistical average-ers for the input data. Which means their output is always going to be generic and average. Generic and average ideas are going to at best lead to a generic and average essay.
What lecturers want to see is that you've done the reading around the subject and come up with a novel approach to things and see how you carry that through. This doesn't mean reinventing the wheel but just finding a particular "hook" into the topic which is unique to your writing and your essay.
Also the point of the assignment is not a transactional process where you output a bunch of text and get a grade in return, but where you learn the reading, research, and writing skills to create that piece of work. Note that "writing" here doesn't just mean the end output of the text itself but the process of constructing the argument(s) you are using and how you piece them together.
Using generative AI tools for any part of that just means you get a grade but can't actually do the work, which means eventually in your life you're going to be at best a mediocre and easily replaced employee because you never learned to actually do basic critical reading, research and analytical writing for deadlines...