But since I can’t use Amber on anything except Android, it doesn’t help me much.
Discussion
Yea iOS should have an equivalent. Nostore is a good signer but still has internet permission of I'm not mistaken. I'm not comparing amber to a password manager. Amber is a signer. It's role is more than password management. It's nostr key management. Inherently more specific in its use case.
Nostore (deprecated) was replaced by Nostash (a fork by nostr:npub1yaul8k059377u9lsu67de7y637w4jtgeuwcmh5n7788l6xnlnrgs3tvjmf) that works fine for browser clients using Safari, but there isn’t anything that can sign inside apps.