Your question implies that you already have a high-leverage broker. Ask your broker whether you will be able to maintain your account after you move to the U.S.
If your broker says, ‘No, your account will have to close’, then you have only 2 choices:
(1) Open an account with one of the OFFSHORE BROKERS that will accept U.S. residents as clients.
(2) Settle for 50:1 maximum allowable leverage from one of the 5 U.S. forex brokers.