Would seem to me that generating key in foundation then importing into Amber would be the more secure second step. That way Amber is the only app that had the nsec. This is awesome for generating nsec offline.
Did you know you can use Passport to generate, backup and export your Nostr keys effortlessly? 🔑
One user gave it a go and was blown away by the seamless flow with nostr:npub142gywvjkq0dv6nupggyn2euhx4nduwc7yz5f24ah9rpmunr2s39se3xrj0

Would seem to me that generating key in foundation then importing into Amber would be the more secure second step. That way Amber is the only app that had the nsec. This is awesome for generating nsec offline.