I’m in a similar position. My O-A Visa expires 1 July 2023 as does the associated requisite insurance.
If I renew my insurance it will be for one more year running 1 July 2023 to 1 July 2024.
The question is: Can you just arrive back in Thailand before 1 July 2023 with the original valid OA visa and the new insurance certificate and this will allow you to be stamped in for a further 12 months? Is that all that is required?