This may be old news by now, but here's how I've accomplished it:
(I'm not sure if the first step is required, but it can't hurt.)
1) From the Notification button (LR corner) > All settings > Accounts > Sync your settings: Switch on the Internet Explorer Settings and whatever other Windows items you want to auto-sync.
2) (Windows key + R) > gpedit.msc
3) In the left pane, Computer Configuration > Administrative Templates > Windows Components > Microsoft Edge
4) In the right pane, double-click on Keep favorites in sync between Internet Explorer and Microsoft Edge
5) Select Enabled, click OK, close the editor
Not sure if a reboot is required, but I did and it took a few minutes before IE and Edge were synced. Favorites added and/or deleted from either IE or Edge will now auto-sync. XMarks will continue to sync between Chrome, Firefox and IE, while the Group Policy will keep IE and Edge in sync, making all four synced.
Best Answer
You can't. QNAP Help: Why can I not log into NAS FTP with Microsoft Edge?.
A possible to solution would be to use either of those other browsers or use an actual FTP client like FileZilla or similar.