if "Speak" was used, following Select All, in iOS notes, is that audio stored anywhere on iPhone or in iCloud?
I don’t think there’s a global undo buffer for iOS notes like there is for macOS notes with versions of documents being stored like TextEdit.


There is a “deleted notes” section you can reference from the notes web app, but it’s not like Time Machine for going to an earlier version. 


I think you might need to change how you listen. Is it possible to speak from an insert point and not speak from a selection? That might lessen the chance of losing data you can’t restore.