Thanks for the heads up. I made an appointment with another dealer, a couple weeks out due to my schedule, and will call them on Monday to confirm that the warranty covers it. I'm already diagnosed (not by customer complaint, just by them having noticed during unrelated service... hopefully that's equivalent) so I'm not too worried about a diag fee.
Also thanks for that image... I searched the number on it and found the full document (actually a newer revision) here:
https://static.nhtsa.gov/odi/tsbs/2022/MC-10214801-0001.pdf
Glad to see that it explicitly mentions my particular diagnosis of failed thermostat housing (which is what I've been wondering this whole time), and that's bogus what you're going through. I'll report back after I'm done.
P.S. Hold up... $147 for a rear wiper blade... I am in tune with the situation of dealership service pricing, but that is just somethin' else. The OE part is $6.99
here and the labor is less than 1 minute. And an oil change should be closer to $90. Although $350 is a great price for DSG service (but I kind of doubt that line is truly DSG service, "automatic" typically means slushbox).