@xenodium is almost single-handedly creating the possibility of org-mode being as cross-app usable as markdown, and I _heartily_ appreciate it.
The problem that org-mode and Markdown face is that they are fairly minimal. It's common to use plugins, that aren't supported everywhere. This kills portability, which is a core "selling point".
I have seen it happen it Obsidian and Logseq - but even GitHub has a slightly altered Markdown spec.
Org markup is fairly rich. Journelly is my 4th Org app on iOS. Neither has required additional syntax/plugin to cover my use-cases.
I would say maybe it's the opposite for Org. My apps implement a subset of Org features and, because its plain text, the user experience degrades fairly gracefully.
edit: This doc still blows my mind https://doc.norang.ca/org-mode.html