Sensitivity to gross noise on battery charging lines of Lightning connector
I'm not sure how well this answers your question, but it seems the whole basis for your post is an assumption you've made about the experience you had a long time ago with an iPod Touch:


  I am guessing that cranking the ghetto blaster caused damaging electrical noise to spike into the iPod Touch.


As you indicate, this is just a guess and there's no way to know what the actual cause of the iPod Touch battery no longer maintaining a charge was.

My experience

What I can tell you is that during the past 11 years:


I have personally owned 6 iPhones, 3 iPads, 1 iPod and 2 Apple Watches
My family has owned 17 iPhones, 7 iPads and 5 iPods
All of the above devices were charged on a regular basis using the 12v sockets of various motor vehicles, campers or caravans
We have used a range of 12v USB power adapters ranging from about $4 to $50 in cost
We have never come across any damage to any of our devices regardless of the vehicle, socket or adapter being used


In all of that experience, the only damage we've noticed is that cheaper adapters and cables end up failing sooner rather than later (i.e. sometimes they just don't work, or they blow a fuse in the vehicle). However, all iPhones, iPads, iPods and Apple Watches have survived without any damage whatsoever.

Finally, as all of these devices have internal batteries, they're less likely to suffer damage as a result of electrical noise or spikes.