Thomas Reed, for MalwareBytes:
Two iPhones can be connected at one time, and are connected for about two minutes. After that, they are disconnected from the device, but are not yet cracked. Some time later, the phones will display a black screen with the passcode, among other information. The exact length of time varies, taking about two hours in the observations of our source. It can take up to three days or longer for six-digit passcodes, according to Grayshift documents, and the time needed for longer passphrases is not mentioned. Even disabled phones can be unlocked, according to Grayshift.
Nothing is safe. Encrypt and delete constantly.