I debated allowing this post to appear tonight as its 11:00pm here in Thailand.
But to start...
What does your OA extension of stay show as your OA insurance expiration date?
You have to have OA compliant health insurance to initially obtain the OA visa in your home country...then to extend it in Thailand requires the 400,
******
,000 inpatient/outpatient health insurance from an approved Thai insurer.
To cut to the quick...the least extensive way to meet the
******
health insurance is to buy the LMG OA policy.... Issue ages thru age 74.
To leave and reenter Thailand will require the US $100,000 COVID health insurance for the time you will be stamped into Thailand on arrival.
The rates for the COVID ONLY policy may be higher than that of a new OA compliant health policy
If you are from a hi covid risk country such as UK US Poland etc
With your age known and what your passport nation ...is how I can better advise you.
As it may be best to buy a new one year OA compliant policy which has both insurance needs covered.
You asked do you need health insurance to return...
YES...OA COMPLIANT. as you are on an OA based extension of stay.
And will also need have the insurance include cover for COVID $100,000 in medical expenses.