Lol. All these u need to see the files u transferring and is there any medium when transferring as well. Next is that all HDD have speed limitation. Be it SAS or SCSI connector as well. Still won't hit those SSD speed. As for your connection one is direct to PC (DAS USB 3.0) and another needs to go trough your router then ur NAS.
Anyway even with USB C will be almost the same as your USB 3.0
If speed is your concern why bother with HDD?? Just get a SSD
