@DCoartney It sounds like you're going through a lot with this car. It seems some have been luckier than others with NMS Passat, the other thread with high mileages prove that some can go far beyond expectations.
Now, I don't claim to be a car expert, but what comes to mind is a video by Diagnose Dan on YouTube. He was diagnosing second turbo failure, I believe in a petrol Audi, just a few days after dealer installed the replacement. He mentioned dealer's fallacy was that they did not investigate the CAUSE of failure, only treating the effect. What ended up happening was a clogged oil feed line to turbo. The old broke due to oil starvation. New was installed and again failed as the oil line was 100% clogged. Now, VW has a TSB that basically requires all lines to be replaced including oil pump. After all, turbos are not supposed to fail this early! Did you receive a copy of the work from the turbo replacement? Do you know if they completed any additional work beside turbo replacement itself?