I thought this is a question on Cyberduck which is a standalone app, which hence appears in the list of open application (CMD-TAB and in the dock with an activity indicator below its icon/name).
But your question is regarding Mountain Duck, which is an integration into the filesystem (APFS) / filebrowser (Mac Finder). I don't know this product. And I'm not the software developer, but only a user like you. I hope someone else can provide help to you. Good luck!