America is a very large country and I’m sure if you paid enough, and took the time to train the workers you can find people to do the work. If you have planned your budget and timeline around not taking this path then it seems unethical to me.
I’ve witnessed tech jobs done where there are plenty of capable people in the us available to do the work. They just cannot afford to post us wages and train the workers in the us.
I completely understand that some projects are different, and you need a specific skillset. But if you are going to do work on us soil you have to follow the law.