I have move-marketplace-link-to-profile-dropdown turned off, however the link still does not appear in the header links.

Needs to be moved to the feature
For now you can override the css rule from above.
Indeed the CSS is the way to go.
But since the feature name is unclear, I'm leaving this open for a bit if anyone wants to:
elementReady like in trending-menu-item to detect the header link, remove it, and add the link to the dropdown.
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For now you can override the css rule from above.