UPDATE: I spent an evening sanding the crankshaft and conrod journals, getting them to a state where they weren't smooth to the touch but they were operationally smooth. Plastigauge read that they were still within clearance spec, and an old-timer on a youtube video said not to worry too much about indents running around the bearings, as oil would simply fill those little gaps (not ideal, but not a show-stopper). So I reassembled everything, and the car has been running smoothly for a week now. This weekend, I'm going to drop the sump and verify the state of the oil, conrod/crankshaft play, and the status of the bearings. Looks like what VAG said was impossible, not giving any information in the service manual for bearing replacement saying that as soon as you even undo the crankshaft bolts the engine block has to be replaced, is in fact doable—at least in the short term, as I now need to monitor for longevity—but so far so good!