OK, here is some more info about the subject:
I have Aetna insurance covering 1 million baht, and i am on a RETIREMENT visa. I called to Aetna to check if i need to upgrade to 3 mill baht for a renewal of my visa. They told me that the rule of 3 mill is not applying for those who already are here on a Non immigrant visa UNTIL 31st August 2022. So everyone that needs to renew before that date does not need the insurance. However after 31st August 2022, we need to check again if there is needed.
Hope that gives somewhat a bit more clarifications than the article.