AllieBlue ☉ on Nostr: Help again. I have a various npubs But only one private key Alby has my private key ...

Help again.
I have a various npubs
But only one private key
Alby has my private key
How do u generate a new private key for a new npub?
Example how fo I generate an Amethyst or Primal net private key for my npub here?