Did you consider ditching the OA visa and changing to a NON O while you are home, so you can try to avoid the long insurance requirement? Then you just need the COVID insurance (which your current insurance covers). You can then get a year long extension of stay in country by transferring, and showing, the required funds in a Thai Bank account. Something to consider at 70, with insurance options difficult to get. Also other options are to change to a NON O retirement visa inside the country, and then extend that. I am sure someone will correct me if I am wrong.
Ah yes OK. A completely new visa for a different reason. Yes OK that make sense. Ellie said "a new visa with an extension before it expires?".....I think she means....just a completely new visa for entry. No relation to the old one. There would be no extension of anything involved. Got it.