I ship about 30 packages a week on USPS and things are definitely getting back, close, to normal. Still a few exceptions; but nothing like what was happening in December. The oldest , outstanding, package is at 4 business days. And, these are all First Class. Many First Class have been delivered in 2-3 days in the last 2 weeks.
We have the same carrier for the last 15 years and she would usually come by about 2 PM; during the crush it was 6PM. So; they were putting in some hours.