I’m confused. Where are you planning to do this research?
Your plan is to come and work in the US? Is that why you have decided that the US is your only option?
I have to agree with @DadOfJerseyGirl, that according to your needs, of “All or None”, for a US research position, you’ve restricted what you are willing to accept.
It seems that if you want an RA position, without any knowledge of how the US educational college system works, that you really are in dire need a reality check. That, in itself is very difficult. But, you also want to do this in the US, so, as a non-citizen, you would need to be sponsored. In the US, a sponsorship would have to go through US immigration.
There are thousands of students who want to be sponsored. There is a very long line because, US employers are mandated by US immigration laws, to find and employ US citizens first and foremost. It is very difficult for a non-citizen to find positions available to them. Employers do not want to hassle with the paperwork, expense and time of sponsoring a non-citizen.
I understand that it’s your wish to redirect your goals, but unless you choose something that will work for your situation, you may be stuck.