Unable to correctly format an external 4TB SSD

I have just purchased a Samsung 860QVO 4TB SSD. its mounted in a 4 bay drive enclosure and is connected to my MacBook Air via USB 2.0

not the best connection methodology I know - but its the best I can do

This enclosure previously held 4 x 2TB HDD and worked great until the drives wore out

When I go to format the new drive - disk utility sees it as a 1.8TB drive and nothing I can do will get it to see it as a 4TB

any ideas/solutions gratefully accepted