Non-OA an the STV are the only visas that require health insurance, that's different than Covid insurance. Everyone entering Thailand requires Covid health insurance, reguardless of their visa.
Based on your profile I'll assume you're an Indian passport holder. If you choose a visa on arrival, the cost is 2000 baht and only valid for 15 days, and you cannot extend that in Thailand.
If the Thai embassy in ND is up and running, I'd try and get a single entry tourist visa (good for 60 days) before you come.