@andrew
I have been using Bear and #ObsidianMD for some time; they have somewhat different capabilities. I use Bear for quick note taking, to do lists, etc, stuff I need access to no matter what Apple device I am currently using. Bear's syncing capability across all Apple device is superb.
I use #Obsidian for more structured writing and projects, due to Obsidians file/folder structure and its code-folding capability. And I can have an outline of the document in the right pane, where the headings can be code-folded independently. Obsidian's capabilities can be extended via plugins. I use Quick Latex for Obsidian among others.