Same here. I came over in 2019 just before the insurance requirement. I opened two different Thai bank accounts, just in case. I chose Bangkok Bank and Kasikorn. I had to come back to the US to earn a bit more money and savings prior to fully retiring, so now I am sending money (via WISE account) into both accounts slowly. Keeping most of my funds stateside until I actually move over on a permanent basis in a few years.
AXA has minimum insurance, high deductible and reasonable price. It's basic, but it will do the trick for the OA. Once in Thailand, get a Thai bank account and then work to deposit the 800K baht need for the O visa. The O does NOT require insurance.
Only two years until 50. That's a blink of an eye. In the meantime, visit and then if you fall in love with Thailand, on that visit...prepare, prepare, prepare.
I am keeping my Medicare AND living abroad...cuz if an American is spending a minute in the US of A, and gets into an accident or gets sick, they are SCREWED, going bankrupt on even one hospital stay without it. Nobody knows UNLESS you are foolish enough to tell them. Keep a US mailbox always and you are fine.
Start your own multi-million dollar company and then open an office in Thailand. You'll have to hire Thai workers, of course. Get familiar with the laws and procedures. Or if you are a licensed professional teacher, get hired by an international school.