First Time Machine backup, (lot's of files...)

Bought a 4Tb My Cloud Home to use as a Time Machine backup disk. First time it’s a lot of material to backup, like 400Gb, so I wan’t to connect the disk directly to the Mac so it’s a bit faster. Can I use a Ethernet cable between the disk and the Mac or should I connect the Mac to the router via ethernet and keep the disk plugged into the same router?