Nexus 5 Stuck in bootanimation with flying dots (No usb debugging)

Hi,
I have this nexus 5 which was not rooted, the usb debugging option is off and the bootloader is in locked state as nothing has been done on it in the past.
The phone is stuck on flying dots animation. I have tried various methods but all require usb debugging to be on. How can I go back to stock without having to turn usb debug option on? I have seen some mentions of fast oem unlock, but how do I do that?

Thanks!