For an interesting micro example of immigrants abandoning the Republican Party, I could cite my business partners in Detroit from a few years ago, Chaldean Christians of Iraqi origin. Most of their families had immigrated to the United States after the first Gulf war, and a thriving, financially prosperous community soon solidified in the Detroit area.
The Chaldean community were rock solid Republicans, and when the time came they became politically active Trump supporters, doing lots of fundraising and get-out-the-vote drives.
Then, when Trump came to office and began his anti-immigration push, the Chaldean community got hit with a deportation hammer.
People who had lived in the United States for years or decades saw their paperwork going over minutely. Everything got questioned, and not in a good faith way. One of my partner’s elderly grandfathers, who was barely able to look after himself and who did not have family left back in Iraq, got thrown on a plane by callous federal agents who didn’t care how he was going to survive.
This happened over and over again. These new Americans and staunch Republicans were treated like unwanted scum. Just because of where they came from, and obviously because they are not white.
Suffice it to say, the bulk of the Chaldean community in Detroit is no longer Republican. They have learned all about Republican white nationalism.