@Tof_Jossic You're correct. Also, If the breakdown summary is not accessible to certain audiences, the copy option will not be visible. This typically occurs with newly created audiences.
@MktgCloudUser What's the email address written on the personalEmail.address will be taken to send out the message by default. Verify you have a valid email address in this field.
@MontexHo, Nothing has changed recently, and take a look at this documentation on journey action id and message id details. You should be able to use the data attributes mentioned in the documentation to create an audience based on email engagement.