You’re in the implementation phase already while I am still in the requirements phase!
For me it’s important that:
- my data can be handled by multiple applications. I tested The Archive and Obsidian at the same time and when working on the same file with one application, the changes showed simultaneously in the other. Now that’s nice but not a prerequisite,
- my data can be transformed to another OS platform (Unix, Windows, macOS, Linux, ChromeOS) without having to be converted. So data standards should be the same on the platforms or else the platform is not my choice.
- my data will NOT be required to be uploaded into an application; f.i pre-iPhoto I stored my jpg files in my filesystem with folders named by me. Now they are all in Photos in I don’t know what format (heic, jpeg, jpg?). If I ever want to go to ChromeOS, I will have some work to do.
I am able to export from Agenda without much problems, but it has to be done with one-by-one note at the time. MacJournal exported the whole database to txt-files per Topic. Evernote is a day-job and Onenote is a total lock-in. Your text-notes there can only be exported to pdf’s. Many more examples to go. Sometimes it’s a lot easier than other times. So, better is to keep data outside an application.
Now you mentioned .md files but I prefer txt-fles. The Archive could work with txt and md, but had some other negative features. Obsidian can only read .md files, also no good. When using standard txt files, any Markdown can be done, when needed, to publish in text or HTML or whatever. I did not look into other data-standards, but pdf’s look fine. etc.
If there is a data format selection needed in order to come to an open standard, it should be done without the OS industry. Until that time I will go on in my own amateur-way.