One option: Schwab offers international accounts that can help once you lose your address and can no longer open any US accounts. You can't use ACH or their roboadvisors, however they do pay ATM fees internationally.
I use Schwab and recommend them. Open an account before leaving the US. You don’t need an international account, use a US address. If Schwab ever asks if you live overseas tell them no, you just travel a lot. They asked me once in six years, accepted my answer. They refund ATM fees on the regular investor checking account too.