I recently sent a coin to a large German auction house using USPS priority international. Registered mail was not an option for some reason. It arrived in Germany and cleared customs in Frankfurt in eight days, then was transported to 4 different locations until it arrived in a "pickup location" and has been sitting there for 3 weeks. I inquired with the auction firm to confirm they had not yet received it. They immediately replied that the "pickup location" was the local customs office. They have inquired with customs and were able to confirm that the package was indeed in the local customs office. They informed me that this is not an unusual delay in their recent experience, and suggested it should be delivered to them any day.
We're actually in a "perfect storm" when it comes to shipments from overseas through or via the USPS. We have a pandemic, an economic downturn that has affected the airlines, which have drastically reduced the number of flights, and changes made in June at the USPS that have effectively significantly affected delivery times, especially for items sent by first class mail (tracking or no tracking). The private delivery services appear to be unaffected. I had a shipment from France arrive within three days through Fedex. However, anything sent by first class mail from overseas can, and will, take a very long time to arrive. I've had one shipment, first class with tracking, from Israel, in the pipeline since July 6th. The last tracking update was August 18th. I've submitted three search requests, one still being processed, but the other two responding with "letter in transit, not received by post office", or something to that effect. I really feel badly about the situation at the USPS. The staff must be suffering morale problems and I only hope that the situation turns around within the next two or three months.