In not mixing anything up, nothing has changed besides the coverage amount. And no, non immigrant visa holders don't need covid insurance for the duration of their stay.
So because of covid, everyone entering Thailand right now requires Covid insurance for atleast the 1st 30 days. You can use travel insurance, the certificate must specify they you're covered for covid treatment in Thailand up to $50k usd.
Separately, the Non-OA visa requires health insurance. If your policy covers covid treatment (which it does, they all do) then you can use it, you just need them to send you a letter/certificate stating the above.