I thought I read a post where the idea was that something plugged into the data port or even the charging ports could do something or other to keep something or other from sleeping totally. That was my takeaway.
If the port your plugged into powers-off when you turn-off the car, it shouldn't matter. Stuff plugged into the OBD2 port will keep things awake because there's a wire running directly to the battery. The infotainment system has a slight draw to keep the clock and station programming active. You can test the USB port by plugging something like your phone into it, it should start charging - turn-off the ignition to see if the port dies - no power no system drain.
On the 2012 that I drove for a dozen years, it was perfectly fine for the car and battery, but eventually killed the flash drive. I'm fairly sure the flash's damage accumulated while the car's ignition was turned on, not off.
^ Yep constantly electronically hammering away at it, will eventually kill it. Add to that the internal car temperature exstreams. Luckily, flash drives are cheap an plentiful, so hopefully you've got several backups waiting in the wings......
