When login with Amber?
PSA: pretty soon, NIP 04 DMs are going away, and will be replaced by NIP 24 DMs. The current version of Coracle's DMs can still be accessed at https://nip04.coracle.social, which I will link to from within the new version of Coracle as well.
Discussion
Better nsec bunker login first!
On Android?
Who is it that has nsec bunker?
Well, I think Amber will probably support the same protocol, but remote key storage seems best to me because it covers all platforms with a single key management app.