If the passport is Hong Kong dt (fake transit), will it affect going to other countries?

DT is just a bad record written for you by the Immigration Department of the SAR. It's because you didn't really fly to a third country, but went to Hong Kong in this abnormal way, which is a sign. A passport can only be DT twice at most, and the third time will be blacklisted by the Hong Kong Immigration Bureau (you can't go to Hong Kong by visa+computer ticket), but the bad records of the first two times will be cleared with the replacement of the new passport. DT is only written on the passport with a pen, and will not be recorded in the computer. To sum up, signing an American visa with you has no effect.