Encrypted HD takes ages to unlock

Part of our backup strategy includes cloning our Macs to a portable drive (LaCie Rugged Drive with platters and TB3/USB-C) that we store at home. Except for one, all volumes on the drive are encrypted.

When connecting the drive to one of our Macs, it’ll take several minutes until the machine has gone through all the password dialog boxes for decrypting the volumes. With previous, similarly encrypted drives, it didn’t take nearly as long, and I’m wondering if this might be related to the partitioning of the drive.

Currently, this is the drive’s layout:

  • Drive (GUID Partition Map)
    • Volume A (CoreStorage Logical Volume)
    • Volume B (CoreStorage Logical Volume)
    • Container disk5
      • Volume C (APFS Volume)
    • Container disk3
      • Volume D (APFS Volume)
    • Container disk6
      • Volume E (APFS Volume)

Do you have any suggestions on how to optimize this drive? As long as it’s promising to speed up the mounting/decryption process, I wouldn’t mind wiping the drive and partition it from scratch.

Thanks for your help!