2018 Buick Envision ELECTRICAL SYSTEM,AIR BAGS,BACK OVER PREVENTION

Multiple Electrical parts became faulty starting with 3 tire sensors, then the front passenger airbag sensor, immediately followed by both rear sensor control modules. Milage at onset was approx 85000. Brought to dealer for dx due to my vehicle applying breaks when it shouldn’t, when auto start/stop was still on, the vehicle powersteering would stop working intermittently when going from a stopped position in drive to accelerating. Dealership ran diagnostics and determined the air bag control module is faulty and requires replacement of the entire seat to replace the sensor, as well as both rear sensors need to be replaced . This vehicle has been in no accidents. I had a second opinion completed with the same diagnosis. Now today- my OnStar system began blinking red and forcefully called OnStar twice. I spent over a half hour on the phone while they tried to reset the system and the car wasn’t responding as they would expect it to. There is something VERY wrong with the electronics of this vehicle, I dont feel safe in it . Please advise