“MS Word like experience” is a bit of a red flag, since MS Word is full of issues with formatting, and complexity. I assume “WYSIWYG”, a term that peaked in the early 90’s (check Google ngrams), and is not used much anymore, is actually code for “rich text”. So, what kind of rich text would be exported? Word XML (.docx)? RTF/RTFD? Some sort of Dynalist XML?
Rich text is far less portable than Markdown. Far less.