sn-rme VS QOwnNotes

For example, here's one editor that you can add to standard notes:

Standard Notes, if you want something higher security (zero-knowledge, end-to-end encrypted). The free version is very basic but you can use third party extensions without a subscription to make it more usable (I use Rich Markdown Editor, see this page for others).

According to this post on r/StandardNotes, you need to use a third-party extension like https://github.com/arturolinares/sn-rme

Hey u/Flazyy! Experiencing comparable behavior on my end. Sounds like it could be related to Rich Markdown Editor specifically—considering you've made sure the syntax is correct, no themes are affecting anything, and the behavior is present across multiple platforms and instances of the app.

I use the Rich Markdown Editor extension which works like a dream: https://github.com/arturolinares/sn-rme

I don't know of an ideal solution - the closest thing is the Rich Markdown Editor. It can do checklists and links but not pictures. The UI isn't the same (access options by tapping a "+" at the beginning of the line) and all youtube links are automatically embedded unless you remove the "https://" at the start of the link.

I don't have a sub and was able to install Rich Markdown Editor for Standard Notes.

It doesn't, but you can use a third-party extension like this one https://github.com/arturolinares/sn-rme

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.