Assuming you are in Thailand on a marriage extension of stay obtained from Phuket immigration based on your non-O visa for purpose of marriage...
You will first off need a re-entry permit from Phuket immigration (1,000 baht for a single entry, 3,800 baht for multiple entry) that will allow you to keep your current permission to stay when you re-enter Thailand.
Under the current rules for Phuket Sandbox (which may or may not be in effect in November) you would need to be fully vaccinated. You would need medical insurance for covid with a minimum coverage of $100,000 USD for the period of time to completely cover your current permission to stay. Note that the insurance is normally sold in standard durations (1 month, 2 months, 3 months, 6 months, etc.) so you will need to purchase one that covers the entire period of your current permission to stay.
Because you are on an extension of stay due to marriage you do not need the general medical insurance that is mandatory for Non-OA visa holders.