The cleanest way to leave Word is the boring one. Drag the .docx file onto the editor. The heading hierarchy comes through. Lists come through. Links come through. Inline formatting (bold, italic, code) comes through. Tables come through, more or less, depending on how Word stored them.
The file format you’re leaving doesn’t get to set the cost of leaving. Word can be the world’s most-used document format and still be the format you stop using on a Friday afternoon. The import side has to handle the messy parts: the smart quotes, the tab-indented paragraphs Word pretends are bullets, the empty <w:r> runs that mean nothing.
PDF, plain text, Markdown, the same story. Drop the file, get a sweetdocs document, keep what mattered, drop what didn’t.
Importing isn’t a moat. The moat is what happens after you import. But the import has to be free, fast, and dumb to use, because the friction of leaving is the only thing keeping people in Word.