With missing packages, I have had a lot of luck filing a “missing mail” inquiry through their website. I don’t have any idea exactly what it does, but I have had a number of packages “IN TRANSIT TO NEXT LOCATION” in the last few years. Virtually every time, the package starts moving through the USPS shorty after.

Try it. It costs you nothing and possibly makes a USPS employee somewhere have to figure it out.

Good luck.