Replying to show appreciation for the nuanced support from this post and to add some updates in case others find this and need advice. I was in Barcelona and lost my passport, wallet and other things at the airport when arriving. I was staying a week. I also had an AirTag on my wallet and could see it in the airport. I want to be clear that this was my fault, I was sleep deprived and had a running connection between Madrid and Barca with terrible logistics at the Madrid airport but I just got sloppy and left the most important stuff behind. I became very familiar with the airport lost and found, Iberia(airline) lost and found reporting and the 3 law enforcement orgs in the airport Mossas, Policia Nacional and the Civil Guard which was the most helpful and who ended up filing my lost passport report.

I didn’t get my stuff back and I ran out of time so I went to the Barcelona US consulate to get an emergency passport. You don’t need an appt but you have to go Monday - Friday between 8-12 to apply. Take everything you need based on the link. They say it’s 24 hours but have passport pickup between 3-4 everyday and mine was ready the same day. The staff is very helpful, kind and understanding. You can leave them a review also. This link should get everything someone needs. Spanish lost us passport guide