I don't think there's a lot of evidence that the day-laborers and other semi- or unskilled workers that are here without documentation are actually competing with semi- or unskilled U.S. citizens for work. Would be happy to look at evidence that shows I'm wrong. There is a very strong correlation between the amount of immigration to this country and the joblessness rate (i.e., the lower the unemployment rate, the higher the immigration). Unsurprisingly, most people come for the jobs.
The point about Musk is important: the response is, well, he's a productive member of society--but that's a backward looking argument; he wasn't a bazillionaire when he was an undocumented immigrant. Also, he's obviously an outlier because of his massive wealth, but I think there would be pretty broad agreement on immigration if the standard were that: productive member of society. There's a lot of evidence that undocumented immigrants contribute a great deal to our economy. But I know that many of you don't believe the studies that I've seen; for whatever reasons you think those studies can't be trusted/must be wrong.
And before we all go down a bunch of rabbit holes--I'm just offering a perspective, I think one that was solicited.
