> Also note that they talk about these being "drive-managed SMR" drives, and they are, but they reportedly don't advertise themselves to the OS as being drive-managed SMR, as they're supposed to do as per the ATA specifications (unlike other WD DMSMR drives which do). They literally designed the drives themselves to lie about this.

I wonder if reporting to the OS that it is a SMR drive would kick in host-managing SMR code paths that conflict with how the drive managed SMR works. While I'm not terribly inclined to give WD the benefit of the doubt, this seems certainly possible. It seems like it should be possible to test by modifying whatever part of the Linux kernel or userspace tools control this and having it use the model number instead of what the drive reports as its SMR status. Granted on a closed device like a Synology NAS, this isnt possible for a user to do though Synology themselves could, and probably should test this.