It may be a coincidence, but shortly after the latest security update my S10e is no longer recognized by my car (2018 Honda Civic Si). I tried different cables and even did a factory reset but it still won't recognize it at all.
I was also able to connect an iPhone just fine so I'm pretty sure it's not the head unit in the car. Any ideas?
Have you tried resetting the Network Settings on the phone? This article explains more, (even though it mentions a different type of car). http://www.samsung.com/us/support/troubleshooting/TSG01200675/
I did a complete factory reset, hard reset the infotainment system, and successfully connected with 2 other android devices (Pixel 3, Pixel 3XL), but was still unable to connect. Fortunately, I got it figured out...
For whatever reason, when I connected the USB to the car, it was defaulting the USB to file transfer. As soon as I changed the option to MIDI it started working. Not sure how that setting got changed, but I'm glad I got it figured out.
Do you know if there's any way to have USB default to MIDI? I went into developer options and changed it, but it still defaults to file transfer.