I have a 2018 NX300H and upgraded to Apple CarPlay using Lexus Dealer. I don't know if this is a coincidence but recently i have been using CarPlay on long journeys and since then my Usb port has failed twice. The first time i swapped out the small usb module myself and it fixed the problem instantly. I carried on using CarPlay and the USB port has failed again! I have ordered yet another unit to replace it. The unit is very easy to change using the steps below.
Empty out your armrest box area
Do not power up the car
Remove any usb leads or other aux leads
Gently prise out the small module using a thin blade
Pull free until you see 2 cables and connectors (it is a tight fit) tie some string around them so you don't lose them back into the hole.
Gently prise the 2 cable connectors free using a small terminal screwdriver
The unit is then free, do reverse to fit new one.
Looking at the forums I think this is a common problem with this unit and MAYBE having the connection to CarPlay makes it worse??
Attached are the details of the unit for NX & I believe UX, maybe others as well. Hope this helps you guys.