I forgot to do this update: a year ago in last November, the TDI suddenly started making a clicking noise from the engine. It had just a few weeks left of the dieselgate warranty, so I flat towed it to the dealership. I suspected just a plastic timing chain tensioner- a cheap and easy fix, but they didn't want to tear into the engine and decided to just replace the entire engine plus almost everything bolted to it like the turbo, injectors, etc. without doing any real diagnosis. They first tried to offer me a laughable $6k to buy it from me, but then probably spent about $30k ultimately in parts and labor to repair it for me. They couldn't get an engine from VW, and it took about ~8 months, but the dealership built an engine from individually ordered parts. I also shelled out about $3k out of pocket to replace almost everything else on the engine that they weren't going to do- all of the coolant hoses in the engine bay, etc.
I've had it back now for more than 3 months and it runs perfect. Mechanically it is basically a new car, because almost everything in the engine bay is replaced, and I had already previously went through the rest of the suspension and drivetrain with new parts.
It seems a bit of a shame to replace an otherwise repairable motor, but for overlanding in remote places I can't complain that now every system has been carefully disassembled and replaced or put back into new condition.