Do.in home country for the trailing spouse thing. Yes easy and will save you doing 800K twice. But the other way is ...use and agent and let them do it all for you.
You can get a vaccine passport from US Printing office then go to where you got your vaccines shots and they will enter info officially. It is a yellow booklet like in the old days. CDC and Homeland State Dept and US Gov approved. Accepted everywhere. Also check if your state issues a QR code for your phone. You can also use that.
Unless made here in Thai. Then no import tax. Prices are okay and even a bit lower than US or UK. Used prices are even better... given these economic times and repo rates.
Try Greece or the Caribbean.... easier and less complicated same prices and better weather. Oh... and less beurocracy to deal with getting permission (Thai Pass) to get in.
Everyone... wait. Don't book anything until end of May. This country has no idea what it is doing. The rules keep changing. My local immigration office folks all say to wait as they have no idea either.
If you have booked and done the stupid Thai pass or test and go or whatever silly names they add to describe a confusing mind numbing and frustrating needless procedure... then you are on your own. As