My biggest issue with all these Markdown editors is that the format is text only, forcing other files to be stored independently. It does not support embedded pictures, formulas, etc.
My perfect option uses some format that would allow text, pictures, audio and video, optional LaTeX formatting all in one file, and wouldn't be constrained to a single application that can run it all. At least some apps supporting it should be in a note-taking layout, not a standard office program.
Mobile support would be a banger, too, but is optional.
Essentially, I want a OneNote-like experience without walled garden, bundled in a way that would allow it to be painlessly exported into several other pieces of software, available on Linux.
Any ideas on that?