No problem! You can generate the private and public keys offline and have them directly usable by your application. You don't need Internet access to generate them. You can then import the nsec into an extension or bunker as you suggested too.
You have to publish the profile metadata for it to be able to be read and seen by others on the network. However, once a key is discovered (generated) it's technically possible to follow it with zero metadata available anywhere.
I hope this helps.
