Interview today went very smoothly. We arrived about 15 minutes ahead of schedule, as directed, and security took a few minutes. The agent came and got us about 5 minutes after the interview time, and interviewed us both together. He started off explaining that we had a good case, and that's why he wasn't separating us.
No hard questions, aside from my nerves when he asked for 2019 Tax Transcripts instead of Tax Returns and I didn't have them. He asked some basic questions of each of us (partner's birthday, parents' names) and asked my husband a random selection of the Yes/No questions from the I-485. At the end he had us tell him together about how we met/dated/got married, and there was some laughing and joking around. Then he said "Okay, you're totally married. I think we're done" and said he'd submit the approval on the spot. We got the email notification that the card was being produced within two hours of leaving the appointment.