OP’s application will be compared with other applicants from that country, therefore will be compared with others international students, YET be considered as a citizen applicant(therefore the selectivity doesn’t change). Your application will be most likely be read by regional officer who’s familiar with your school system, and that makes sense!
You will also be categorized as a citizen for financial aid purpose.
However, each college has different policies regarding US citizens applying from outside the US, so
DO NOT USE THE INTERNATIONAL CUT-OFF DATES! Contact each of your colleges/universities, and ASK THEM when you should apply because you are a US student abroad. Then use the dates you have been specifically instructed to use.