hey mike! with Android, you can use a piece of software that holds your key and manages permissions/access to it. this application on Android is called Amber. you can use it with apps like Amethyst, 0xchat, Voyage, Fountain, and then you can also use it as a 'NIP-46' Bunker, meaning applications that support bunker:// signin strings you can use those too. for example, you could use nostrnests.com with Amber to sign in so you don't have to use an extension or enter your nsec. you can install it from zap.store if you'd like to try it out.