Have you filled the oil back up? Low oil level can cause the P0014.
Have you ever replaced or at least cleaned the Camshaft Position Actuator Solenoid CPAS (sometimes called the Variable Valve Timing VVT solenoid)? It has metal screens that can plug up with little bits of metal or crud. This is one of the most common problems and it’s pretty easy to fix. Do a youtube search for “how to clean trailblazer VVT solenoid” or something similar.
If it’s not leaking the oil, then it’s burning it. Time to pull the spark plugs and check them.
Not really safe. The exhaust gases need to be guided away from the vehicle. If the exhaust comes out there it could melt something in the area or worse poison you with carbon monoxide.