x.15a2
I think that this page will answer your questions better than the link you provided:
https://duck.co/help/settings/cloud-save

Regarding "recycling" a passphrase, all that you need to do is enter your existing passphrase then make your changes then click the Save Settings button and your new settings are saved to the cloud.
posted by x.15a2 Community Leader1 year and 6 months ago Link