I would suggest a little bit of controlled testing to better understand what is triggering the reboots. If the trigger can be identified the chance of resolving the problem increases.
- Use another phone (If available) to see if the problem follows.
- Close all the apps on your phone and start the car. Pick one of the apps you use while your phone is connected to the car and begin using it in the same way you would normally. Once you've done everything you normally do for that app move on to the next app. Keep going through the apps until you cause a reboot, or run out of apps.
- Continue the previous test with apps you use less frequently.
- With your phone connected and all normal apps running perform all your normal actions on the Infotainment screen. Things like navigation, placing/receiving calls, climate controls, voice controls, etc. Keep going until you've completed frequent actions.
When the system reboots, does the display in the instrument cluster (next to the speedometer) turn off, or does it stay on and function as normal?