@Carl *************
Ok, the regular Non O still doesn’t have any mandatory health insurance requirements, only the one year Non O-A visa. And the requirements maintains also for your future Extensions of Stays.
That’s why several people on a stay based on a Non O-A visa leave and cancel their visa. Re-enter on a visa exemption or tourist visa and apply for a regular Non O visa in country instead just to get rid of the mandatory health insurance requirement.