What should I know about renewing my Non-Immigrant O-A visa and the related requirements in Thailand?

We are not going into an insurance advice thread

1 - Okay there are two different things

the expiration date of the VISA <- the sticker in your passport and the expiration date of the entry stamp you got when you entered using the visa.

If your sticker expires on 4th Feb 2022 you could exit, re-enter the country and get a whole new year entry stamp (assuming you have the mandatory health insurance required)

Your entry stamp is how long you can stay IN thailand without getting an extension, so right now that's until 23 Feb 2022.

2 - When you apply for an extension based inside the country it's sold as NO entry <- because you're already inside thailand so after they issue the year extension you buy a re-entry permit (single re-entry 1000baht or multiple re-entry 3800 baht)

3 - you can apply for an extension when you have 30 days left on your current stamp (some offices are 45 days before like Phuket, Bangkok, Chiang Mai). At almost all immigration offices extensions based on retirement are issued on the spot (in Jomtien you go back the next day to pick up your passport.

4 - the seasoning of the funds is 800K baht in a thai bank account in your name only for 2 months before you apply. The funds have to stay in the account for 3 months after the extension is granted and then the balance can't go below 400K baht the rest of the year.

Keep in mind you'll need to carry the mandatory health insurance from one of the 18 approved thai carriers, and when you apply for the extension you show the current proof of insurance document that let you stay here this year and the new one that shows you're covered for next year.