read the t&C's about international use. They state that international use is temporary only and if you use internationally for greater than 90 days without us usage they can (and will) suspend you. I don't make the rules, I just read them.
Easiest approach is to "port" your existing mobile number to Google voice. Almost all corps that use 2fa validate the phone number when it is added to your account. I didn't know of any that validate in real-time. Hence if your bank works with your current mobile phone then it should work to the same number in Google voice.
A lot is going to be dependent on your age. Most have 30day exclusion and 60 day for critical illness. Be prepared with medical records for anything you might be taking a prescription for. Also be prepared to have all documents translated from Thai.
unfortunately most don't have the discipline to do at a young enough age to be able to cover costs of a catastrophic illness or injury (including medication).