I mostly use Apple Maps via CarPlay for nav. Somewhat frequently I will start the car and the system volume for navigation is too low and I can’t hear the directions (with or without music playing). I then have to go into the System settings and raise the volume (to about 1/3rd level). Does this happen to anybody else? Anybody know how to fix this permanently?

i think you need to turn the volume up on your phone (as if you’re not connected to the car and would be using apple maps or google maps in its own). I’m guess the car lowers native Nav volume to match phone volume. As an example when my phone was muted, I couldn’t hear any directions via CarPlay when using google maps. When I unmuted my phone sound was back

Wow, I’m glad I asked - this was the exact issue. I must have been trying to turn down music during nav instructions being read out, and actually turning down nav volume. All set now!