What a conversion can honestly give you
A PDF describes where marks go on a page. A Word file describes a flowing document. They are not the same kind of thing, and turning one into the other means reconstructing structure that was thrown away when the PDF was made.
What comes across well: the text, the reading order, headings, bullet lists and tables. That is the content, and it is what you need if the reason you are converting is to edit.
What does not: the exact visual layout, embedded fonts, images, and multi-column arrangements. Reproducing those needs a full rendering engine. Any free converter claiming perfect fidelity is uploading your document to a server to attempt it — and mostly still failing.