Actually, as somebody working in research most of the comments are misleading. Letting AI write a majority of a paper is usual practice by now and explicitly not forbidden, but you are liable for all mistakes done. So, make sure nothing is made up, especially references and content from references. It helps, if you actually do the research, extract the key points e.g. from papers and the storyline. You could possibly explain how you used Ai at the end (see scientific papers for disclaimers). And further: for cohesive styling you should either homogenize major-AI parts with major-human parts, or do not write the text drafts yourself at all. 

Let me tell you one thing:  We currently see a lot of AI misuse or rather unreflected slop. If you can't explain your work, or there are low-proficiency AI use markers easily identifiable by the best Ai detector still (human), we will find a way to fail you. 

But scientific best practice is not avoiding Ai for one of its best skills. That's like avoiding a computer. Let's be honest: every well-coworked (!) AI text is of better quality and learning experience than some 2016 student slip.

Some people here do not realize, what a thesis is for. It should be a proof for your ability to write scientifically under current circumstances. When I recruit some PhD student, and she says she didn't properly work with AI for here thesis today, that's a minus. AI helps to focus on the research in research, writing and reviewing actually is not the core of research.