@Steven ********
How long time have you stayed in Thailand on Non O visa and further extension of stay based on marriage?
I ask because it’s possible to change just your extension of stay based on marriage to an extension of stay based on retirement just at the immigration in Thailand, but this can only be done from your second and subsequent extension of stay.
Then you don’t need to apply for new a Non O in the US first, and you can just get a re-enter permit if you take a trip back to the states.