Yes my 3To HW is ext4 and works great

blkid
/dev/ubi0_0: UUID="efb3206d-a97e-4b7b-a305-a6b061f390eb" TYPE="ubifs"
/dev/sda1: LABEL="3To" UUID="1114621f-a3f4-41de-8862-11f0c228c94e" TYPE="ext4"
/dev/sdb: UUID="0e843820-ead2-4c2d-b53e-da8724078439" TYPE="ext4"

the USB also works it just that is not being displayed and therefore configure from Mount manager