My screen also opens to the apps page each morning. Odd even with the "last" setting enabled. I have experienced the blanked out map on my recent trip. I was able to get it to reset going to the Carplay page then back to home. One time the Carplay map was also blank using Waze, but Google Maps or the iPhone Maps app was ok.
I also get a few glitches in Waze. Not resetting my current location thus it looking like I am still miles away from where I currently am. The symbol will turn (if map view is not set to point up all the time), but I never progress down the road...just sit in one spot. I sometimes get a good result from restarting Waze on my phone...resetting (STOP then Resume) the trip directions...or just going to Spotifiy in Carplay and back to Waze after a period of time.
Only one "1st world issue" was when I am in a strange city, slightly lost and concerned about my particular location not being the best neighborhood, attempting to maneuver the beast through 1-lane double-parked urban streets, and <poof> the map goes blank sending me a twinge of panic. Grab the phone, pull up the still active map...proceed.