Nautilus 43 introduced several breaking changes with libnautilus-extension-4. libnautilus-extension-4 now depends on gtk4. Certain deprecated symbols / headers were dropped and changes were made to separate GTK widgets from extension code. See: ...
This was resolved some weeks ago. I did note that it recurred with the release of Fedora 38, that your repository was not responsive, but as of this morning,
Dropbox is working fine in Nautilus, the file tool.