Hide External Drive icon on Mac Desktop
Solution 1:
You can hide all external disks from the desktop by opening Finder → Preferences → General and unchecking External disks. Then you can add aliases on the Desktop to the disks you do want shown.
Solution 2:
You need sudo, so:
sudo chflags hidden /Volumes/4TB_Drive_BU
After that relaunch Finder: sudo killall Finder