Just a note: Because you are an immigrant to the United States and were not "born an American Citizen" what you did by becoming recognized as a citizen of the People's Republic of China was technically illegal. It would have been different if you were "born an American citizen" and because of the citizenship of your mother or father or spunse, were able to obtain foreign citizenship. However, unless you became a citizen though derivative citizenship (which means your mother or father because a citizen before you were 18 years old), then when you became American, you renounced all prior citizenship. That is not to say some countries like the Commonwealth States will always recognize you as a citizen unless you take some specific legal action, but Hong Kong does not practice Universal Citizenship.
Many people do what you did and never have any repercussions, but you should know that your status is illegal because you voluntarily chose to be an American and abandon all other toes to your home country. I know this from extensive experience in the US Immigration field.
Additionally, you should also be aware that when you travel to Hong Kong or China, you are no longer an American in the eyes of Chinese law. You have lost all consular protection and will be treated as any other Chinese would be treated. The Chinese government will likely not even inform the US government should you ever be detained.
This is precisely why many returning Chinese foreign nationals who qualify for the home return permit and the HK Passport, choose not go get it, especially if they spend most of their time in Hong Kong. Alternatives to the HRP are the APEC travel pass, which in my experience has even shorter lines at Chinese immigration that the line for HRP holders.
Cheers