Okay I have my car back...
I now have my 4th navigation head unit, and radio installed in 18 months, a technician came from Kia corporate (not the dealer) to bring the unit to the dealer and worked on the car, it has been down graded to the previous software version, they also replaced the amp for the stereo, and did some software update for the automatic transmission, the car is back to itself for the moment albeit with older navigation software... At least it isn't that god awful purple 1970s wet dream that came as the latest map/navigation update mid last year...
After talking to the technician from Kia and showing him just how bad the slow and clunky last update was that has killed 2 of the 3 navigation units and radios, he will be reporting back to Kia as the current map update appears too buggy, bloated and slow for the MY19 navigation hardware... Any car after 2020 should be okay as the hardware is updated... Even the current Kia Rio can run the current navigation update better than the 2018/19 Stinger navigation system hardware...
I'm not sure how this will impact future map and navigation updates as my maps are very old now, but at least for now it seem to be working as it should...
Short list of issues:
Head unit was dimwitted and slow on current unified software, menu navigation or button switching from music to radio, or navigation took seconds to respond.
Tapping through music library on USB or Bluetooth took seconds to respond, do it enough times an it would become unresponsive.
Navigation software typing in destinations or selecting a stored address took second to respond.
Intermittently the car would start and have no sound from radio, USB or Bluetooth music but would have navigation prompts or traffic warnings.
Head unit would crash if I pressed options too many times navigating around the menus.
Head unit would crash while driving with no inteaction, taking out the digital dash information and HUD while it rebooted.
Start the car and intermittently the head unit would fully reboot taking up to 90 seconds until the car was ready to go.
Automatic transmission was slow to respond with throttle demand, this was actually scary to drive.
Traffic warnings would be broken audio or not spoken at all, then would be fine.
I provided a list of 15 or 16 bugs and functional issues with the last update software, including things that appeared to be for left hand drive cars, such as the onscreen back button on the left of the centre screen instead of on the right where it was previously.
See how long this lasts, I hope they give me an update on new navigation software, but I don't know when it will be.. Also said it's a 2 year wait list for a new Stinger