I’ve always used a Thai address with Social Security. Last year I moved from Bangkok to Sisaket province. When I got my proof of life letter in Sisaket it said that it was their 2nd attempt. I returned the letter using EMS and never had an interruption in my benefit deposits. I find mail delivery in Thailand to be reliable and reasonably fast for international mail except around New Year’s.
I live in Thailand . I use my sister’s in the US for my bank address. Also keep a standard US phone number for authentication. I use my Thai address for Social Security. I used my Thai address for my Fidelity retirement accounts so California taxes are not withheld when I make withdrawals. I recommend two credit cards, each from a separate bank.