Are you logged in on Primal right now? iOS? Android? Web?
If you can't get Coinos to display an nsec, you may not have given them your nsec at all, so that's good.
If you are logged into Primal on mobile, go to Settings > Keys > Copy private key, and then save it somewhere safe.
If you are logged in on web, I would be very surprised if Primal isn't using Alby to log in. In that case, are you SURE your Alby nsec isn't correct? What public key does Alby show for you? Go to your Alby extension, to the interface that shows your balance and transaction history, and click on the purple ostrich. That will copy your npub, which is safe to share. Paste it here.
