Last day before my subscription runs out, I decided to give it another try.
First incremental update (since I gave up) took ~1h 15m (didn’t time it 100%).
Second incremental update took 13m 22s (4 hours later). Not sure how many items it added, I should have noted it down. It said downloading 210 artwork items at the end.
So while it’s definitely a significant improvement over the previous multi-hour update times, I don’t think it quite hits the mark yet.
Third incremental update took 11m 15s (after watching 3 episodes of a TV show). It said downloading 32x artwork items at the end.