Have you even been to Thailand before? Some of your questions make it sound like you haven't even been here. Come over here travel for a month or two or three get a feel for it to see if it's right for you. I've been here 29 years it works for me, but not for everyone.
I brought only a small bag of clothes. No Electronic. Didn't need any adapters.
When you get here, get a local phone and a local Sim. As well as some of the local apps that everyone uses.
The Healthcare System here is very different from in America and very affordable. If you pay in cash. it's less than your deductible back home.