It's been happening since the pandemic began.
It's worldwide and does not affect only the postal system.
The USPS is particularly hard hit, because of high levels of illness. Still the largest number sick and fastest increase in confirmed illnesses world wide.
So between plant workers off sick or using family leave to care for dependents, social distancing in plants, fewer trucks on the road, and above all, fewer airplanes, all shipping is slow.
The airplanes surprise a lot of people who did not realize that even passenger flights normally carried mail, which was a useful bonus to the airline's bottom line.
The most effective way to deal with this is to change you Handling time to five, seven or even 30 days, which pushes the last estimated date far enough to cover most delays.
Note that you don't change your actually shipping, just the reported Handling time.
Expected delivery 5days, actual delivery 7 days = unhappy customer.
Expected delivery 10 days, actual delivery 7 days= happy customer.
Pro- fewer complaints
Con - fewer sales
Pro- fewer refunds
