In version 14, we had the ability to create a living table of contents, allowing us to quickly jump back and forth between different headings. Unfortunately, this feature was not carried over to V15.
As a result, I now read structured documents almost exclusively in Obsidian, where an outline is generated automatically—and, conveniently, displayed in a sidebar. It doesn’t get any more convenient than that.
(LibreOffice Writer and Typora can do this in Markdown, too.)

BTW: This is also the reason why lengthy legal documents always need to be bookmarked.
https://www.youtube.com/watch?v=66ZqsLOHlVA