As per the title - I’d love to be able to copy and paste melodies and harmonies around without having to either copy the lyrics elsewhere first or selecting the existing notes, deleting, then pasting into the correct voice.
You can use Edit > Filter to select or deselect what you want. If you frequently use a particular filter action, you can assign a keystroke shortcut to it in Preferences > Key Commands.
This is tricky – you can paste notes with chord mode and retain the lyrics, but you’ll also retain all of the existing notes, too! But you can do it in two steps: first filter the notes in the destination passage and delete them, leaving the lyrics behind. Then paste your new music in with chord mode active, and you should find that the lyrics are retained. (Unless I’m inadvertently lying to you, in which case I apologise!)