This seems to be caused by the heavy use of lists (the whole file is a single list).
Summary: using markdown list, the app is unable to “break apart” the different parts of the document to be reused, which causes a full re-render of the list block (which is in your case the whole document).
Normally, when you use proper headings and markdown blocks (generally anything separated by a completely empty line in between), the app can recognize each block, and only re-render unchanged blocks.
It fails to do so with large blocks, such as if you write a really long paragraph, or in this case, the use of a continued list. This means embeds such as images, latex, code blocks, will need to be re-rendered every time, which is causing the performance issue here.
For now, I would suggest using proper markdown headings so parts of the document can be recognized as unchanged.
In the future, I will add some extra optimizations to attempt to reuse more things like embeds. This should hopefully solve most of the issue for this use case.
