It is a bit unclear what you are doing.
It seems that you run OMV5 on a SD card connected to the RPi4 using the normal card slot? Is this correct?
And you have connected some external card reader to a USB port and try to partition and format the 1TB SD card using this card reader? Is this correct?
Is the above is correct, I assume that the card reader may be unable to use a 1TB SD card correctly OR the SD card is defect. Or it may be because your RPi4 does not support this specific card reader. Or it may be because OMV5 is not able to use the card reader or the 1TB card correctly.
You need to figure out what is the problem. You do this by changing things and see if the problem stays or goes away, and use some deduction.
I suggest that you test the card on a PC to verify that it really is a 1TB card and that it is not damaged. Then try to partition and format the SD card from the PC instead, using the card reader. You can temporarily boot linux from a USB thumb drive if you use Windows on the PC. And also run some tests on the card to verify that it works OK after partitioning and formatting. You can also try to run other Linux distros on the RPi4 and try to use them to partition and format the card. And you can try with other cards and other card readers.