Why I am not able to partitin disk (button is grayed out)

It have 1 TB and I cant see full capacity.

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I am also trying to restore it to its full capacity, but this command also done work.

sudo diskutil eraseDisk FAT32 CleanDrive /dev/disk3#

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Could not find disk for /dev/disk3#


Press Cmd ⌘ 2 [or View menu > Show All Devices] then format the entire device rather than just the volume.