The first two attempts the engine would crank but not turn over

The starter "cranks" or "turns over" the engine, so you statement goes no where. I THINK you mean that it does crank/turn over, but wont' actually start and run.

My advice:

1) Stop taking the car to the damn dealer - STOP IT.
2) Order a Camshaft Sensor (I'd order a Crank position sensor as well becuase I ALWAYS carry one)
3) Sounds to me like you MIGHT, might have an O2 sensor bad, but I'd hold off on that for now.
4) Parts are hard with these cars, buying sensors, etc at Autozone or where ever seems to cause issues, I've linked you to where I get my sensors below.
5) Read George's post above.

Here is your Cam Sensor:
https://www.germanautosupply.com/sto...ensor-405.html

Here is your Crank Sensor:
https://www.germanautosupply.com/sto...sensor-96.html

It really sounds to me like the Cam sensor is acting up. The O2 code should not be ignored, but I'm not convinced yet just what that is all about.