I live in a suburb of a major US city, like the vast majority of Americans, natives and immigrants alike. It's a city and suburban area that always votes Democratic and I don't see that changing. I'd have to drive at least 100 miles before seeing a Trump billboard.
A huge number of immigrants to America in the 19th century left their home countries because they felt they had no choice. Millions of Irish, Jews, southern Italians, and others, including a huge number of Scandinavians and Poles (counted as Prussians, Austrians, and Russians because Poland per se was divided among those states) left to avoid starvation, grinding poverty, oppression, or violence. It wasn't all wild-eyed adventurers in search of streets paved with gold. Many stayed in the cities, whose administrations they soon dominated. The exception was the Scandinavians. Most of these people belonged to structured, mainstream religions - Judaism, obv, Catholicism, Lutheranism.
Many of the people who arrived in the US earlier, from England, Scotland and Ulster, brought with them experiences of religious persecution and/ or the experience of being unwelcome planters in a foreign land (Ulster). They arrived in a land where they were often under attack, naturally, because they were occupying land that wasn't theirs. This reinforced their siege mentality.
Some stayed in the fertile land and developed a society and economy that had plantation elites at its apex, the society that eventually caused the Civil War. Some kept pushing west into the Appalachian mountains, where they lived in isolated, self-regulating communities where people depended on each other for survival. These are the people who kept their religious fundamentalism (and distrust of Catholics) alive. You can see echoes of the Calvinism/ fundamentalism in JD Vance's book and his "political philosophy".
The African Americans who arrived here did not come willingly, and their experience of America was (and still is) significantly different from that of all others.
More recent immigrants include Asian and Hispanic populations. These groups both have strong regional influences and a growing presence in major cities, especially in the case of Hispanics. The French and Dutch, who were very early settlers, also had regional impacts. They arrived with money making primarily in mind.
Those who ended up settling the plains and the west were mainly people whose ancestors had been American for a few generations, who went further west than upstate New York or Pennsylvania or Tennessee or Kentucky, mixed in with millions of immigrant Scandinavians and Germans fleeing poverty. The settlement of California was boosted in the early 20th century by the arrival of Mexicans and also the poor escaping the Dust Bowl and agricultural depression in the south east. The African American population of northern industrial cities exploded during the Great Migration. Currently, the south west, Florida, and the north west experience migration from people from the north who are sick of cold winters, or techies. Cities like Raleigh-Durham, Atlanta, and Houston are also growing rapidly as employment opportunities beckon. These cities are markedly different in culture from many of the rural areas of the states they're situated in.
There are several different Americas.