Interestingly, the actual model information doesn't appear to be encoded anywhere in the serial number. So a serial number of WTU060QU0110R would represent a 2021 model year bike that was the 110th bike made in the 'QU' factory on the 60th day of the year. The rep said that the first three digits after the 'WTU' represent the production day (so '045' would be the 45th day of the year), the two letters in the middle represent the manufacturing plant code, the next four numbers represent the bike's position in that day's production run, and the final letter represents the model year (mine turned out to be a 2021 model year). UPDATE: I called again and got a much shorter estimated wait time so I stuck it out.
And my LBS where I bought the bike has actually stopped answering the phones entirely - they're using every warm body in the shop to either work on bikes or deal with the line of customers outside. I tried that first, but got an expected wait time of almost three hours, with no callback option.