Nothing and Sunbird have now pulled their iMessage chat apps following revelations that neither app supports end-to-end encryption. Instead, both are riddled with vulnerabilities and privacy concerns, which Sunbird denies publicly at this stage.https://www.notebookcheck.net/Nothing-Chats-release-turns-to-disaster-with-Nothing-Phone-2-users-found-sending-unencrypted-messages-and-media.770836.0.html
Not the first time One Plus has fumbled the ball on security... They got hacked a bunch of users profiles and leaked accounts back in the day. I would not trust Carl Pei w/ internet security.....
Nothing is completely separate to OnePlus. They might originate with the same person, but not related now.
They could both be terrible with security for the same root cause, but they are definitely separately terrible.