It would appear that only EMS [Express] shipping is working with any degree of speed and reliability.
Some people in Canada are reporting that First Class International is now functional. [Land transport to Canada is possible whereas airplane flights are still rare]
I am willing to test the theory if you are.
EMS boards any available airplane first and 'availability' is a real concern these days.
It is somewhat likely that the Priority package can wind up going by sailing ship taking 6 to 10 weeks
To order by 1st Class mail internationally: Use the Priority Mail selection and note in "Order Comments" that you want it to go 1st Class.
The actual charges will be calculated and the difference refunded.
Priority Mail Express International™ Padded Flat Rate Envelope to Canada $45.95
Priority Mail International® Padded Flat Rate Envelope to Canada $26.90
Priority Mail Express International™ Padded Flat Rate Envelope to everywhere else $69.35
Priority Mail International® Padded Flat Rate Envelope to everywhere else $38.60