I mentioned the ALH TDI from the MKIV Golf/Jetta only, which is a legendary engine, with a ton of them having now reliably reached half a million miles with no major work required. This long predates the dieselgate cars, and adblue was never used on the 4 cylinder VW diesels anyways.
As an aside, yes dieselgate was intentionally criminal, but was sort of the opposite of a quality issue. VW couldn't figure out how to get their engines to work reliability and drive well with current technology at the time and still meet emissions requirements, so they cheated. They had to fix them (I own one) and they are still good, but not as good as they were before the fix- worse fuel economy, less reliable, excessive adblue consumption (in 6cyl models). The ethical thing to do would have been to pull all of the diesels from the market instead, which is what many of their competitors did at the time. Passenger car diesels in the USA are effectively dead because the emissions requirements render them less practical than gasoline cars.
VW had serious quality issues in the 90s that weren't strategic, but were actually causing their company to lose its reputation and nearly collapse. They turned it completely around when Ferdinand Piëch started running things- they were arguably making the highest quality cars at in the world any price point during his tenure as CEO. The quality of current VWs has now fallen back down again, even lower than the 90s cars unfortunately.