I added my US AT&T plan to an AIS SIM card as an eSIM. Works perfectly.
The other option, and a better (cheaper) long term plan, is to port your US phone number to Google Voice $20. You can still make and receive calls as well as receive 2FA sms messages.
if you don’t have $21k USD to put in a Thai money market account, or regular pension payment, you probably shouldn’t be thinking about retiring in Thailand anyway.