At least for the maths and the physical sciences, LaTeX is still often the preferred choice for academic content. There are human collaborative LaTeX online editors like Overleaf in this space, and OpenAI has built a free alternative to that with deep integration of AI, all for free:
The interface is pretty standard, LaTeX markup on the left, preview on the right. Tools will allow you to create figures, polish text, find references (and push them to Zotero) within the specific context of your written paragraph etc. And while you can do this just copy-pasting from a separate AI app, the lack of context and more klunky workflow makes that far less efficient in guiding the AI. There is even an agent mode so agents can do background tasks on e.g. your discussion while you work on the methods for example.
This was definitely built by math/physics majors. I wish they had built this on Quarto rather than LaTeX directly, as this would expand the number of scientists who could make use of this; as at least in medicine, biology and psychology, LaTeX is rare and recommendations are to use DOCX…