What kind of Arduino board are you using? If you do this with a Nano, you're using the CH340G USB-Serial chip to power a motor. That's just insane.
Uhm. No. That's nonsense.
Get yourself a decent 5V power supply, one that can output a few A. Let's say 2A or more.
Then get yourself a DC-DC buck converter that can step down 5V to 3.3V.
Done.