Brakes Failed problems of the 2018 Nissan Altima

While driving the vehicle, notification of "Feb: unavailable front radar obstruction" comes on and stays illuminated for upwards of 5 to 10 minutes before turning off. This occurs when there are no vehicles in front of mine and no road hazards that would have triggered it to turn on. I feel that this is a big safety issue with the way the car is designed to stop when it detects a hazard. This started out randomly over this past summer and in the last week, has been a daily occurrence. When I spoke to the dealership about it, the soonest they had an opening to address it is a month away. No a happy camper, feels like they are not as concerned as I am with the safety of my vehicle. Brake switch failure less than one year of ownership of the vehicle. Unable to push the brake pedal in to start the vehicle. The only way to get the switch to release is to tap on it with a hammer. This issue has been occurring fairly regularly for the past week before I could get it to the dealership today. (is supposed to be fixed tomorrow??) at one point, the vehicle failed to start altogether. Popped the hood to jump start it, and noticed black powdery stuff on the top of the battery as though the batter had gotten too hot and boiled over possibly. The dealership test the battery and told me that my battery is fine and fully charged. This was after I had it on the charger for several hours yesterday so that it would start for me to take it to the dealership.