obsidian-pandoc VS QOwnNotes

First, based on https://github.com/OliverBalfour/obsidian-pandoc/wiki/Pandoc-Templates and https://bookdown.org/yihui/rmarkdown-cookbook/latex-template.html, I created a pandoc template in ~/.pandoc/templates/ and put this latex code in a mytemplate.latex file:

As an aside, if you do any sort of academic writing, the Zotero Integration + Pandoc plug-ins have been a game changer. It is quite an intense rabbit hole (at least for me as a humanities person) that took me to the command line, but one I’m glad I traveled down. In essence, it allows me to thoughtlessly create a fantastic first draft WITH an automatic bibliography…so, so nice to have.

As for markdown, it is much simpler than docx while having the basic formatting you'd need for writing. To export my markdown files to docx for web, I use the Pandoc extension, and you can also install and manage extensions and themes from within the app, so you don't need to code things in manually unless you want to add snippets, which there is plenty of help on the Obsidian forums.

There's a Pandoc plugin too, just so you know: https://github.com/OliverBalfour/obsidian-pandoc

You could use pandoc and specify the twocolumn option (please see https://stackoverflow.com/a/34809186). You could use pandoc standalone or use it through some Obsidian plugins (obsidian-pandoc, obsidian-enhancing-export)

Have you taken a look at obsidian-pandoc?

Have you checked out the Obsidian Pandoc plugin? I think it might meet your needs:

https://github.com/OliverBalfour/obsidian-pandoc

That being said standard Markdown does not provide notation for certain things, so it is somewhat up to interpretation how to convert certain features to standard Markdown.

It does look like the Pandoc plugin can combine documents by processing a master note and any related notes that are linked with the embed link syntax.

QOwnNotes: A plain-text file notepad with markdown support and todo list manager. Tech Stack: C++, Qt.

QOwnNotes

I use QownNotes myself. The notes are saved in Markdown format so that you can easily use them in other programs. An export function to HTML or PDF files is also available, if I'm not mistaken.

A lighter widget based solution that I know of is https://github.com/pbek/QOwnNotes/tree/main/src/libraries/qlitehtml No idea if that can work in QtQuick.

Personally, I use https://www.qownnotes.org. Notes are saved as Markdown files and are therefore easily readable. The rest of your requirements should be met by the tool as well.