Fake drive? Help!

Got this from a friend as if it was new, unopened, it came on a box for a Bosch surveillance system.
All good except it only has 2TB size, not 4TB as described on its label.
Any explanation or suggestion of what’s this or how to proceed is appreciated… It shows as 2TB also on gpt system.

enter the Serial Number into the WD Warranty Status website

if it’s not in the Warranty System … then it’s a fake drive and you’re on your own.

if it is in the Warranty System, and still under Warranty and it says it’s a 4TB Drive … then request a RMA (Return Merchandise Authorisation)

Examine the drive with a tool such as CrystalDiskInfo. This will report the drive’s real capacity.

Examine the drive’s partitions with DMDE. If you see the correct capacity, then toggle MBR Off. You will then be able to reinitialise and reformat the drive in Disk Management.

Thanks for the quick response! Didn’t have the time to proceed on your advises but I’ll report here the solution. Thank you very much!