I found this https://www.seagate.com/gb/en/support/kb/linux-os-support-for-disk-drives-beyond-22-terabytes-tb-218575en/
Linux, like other operating systems, has a 2.2TB limitation in the
Master Boot Record (MBR). Partitions greater than 2.2TB will need to
utilize the GUID Partition Table (GPT) structure
The article is undated, but since it talks about ...
If the 2TB limit is exceeded, in many situations you will be able to detect what's above 2TB and up to the true HDD space, meaning the rest of ~730GB.
This can be a partitioning or controller problem. Some external drives use fake-SATA controllers (software-emulated) and will cause such issues with large drives, because the addressing the controller uses.