I worked for a major tech company that is a household name. In my department of about 60 people, 52 were H1Bs. But, one of our on call rotations required US Citizenship since it dealt with a government client and required a security clearance. Because of this, eight of us had double on calls, and the ITAR one was more frequent. We did not get any kind of bonus for it so that kind of sucked.
The H1Bs got extra vacation in the fall, to go back to India for a month for some holiday that happens, they staggered it so not everyone left at once, though. They got the rest of the normal time off the rest of the year.
Around 2018 the company started doing this weird thing were they obviously tried to trim the US workers. They did things like, required a passport to continue working at the company. They claimed it was for an extra layer of background check. Only 45% or so of Americans have passports, but 100 percent of H1Bs do., so that was an easy low hanging fruit thing, You could apply for one, if you did it immediately, but it took awhile, and they held it against you that you did not already have one. I do not know why it helped a background check, BECAUSE they still could not work on ITAR.
If you work in a majority H1B department, if definitely feels weird sometimes, and like you were not always wanted.
That said, the workers themselves were mostly cool, although they lived in fear of losing their sponsorship, which I think is the bigger appeal to employers than their potentially lower salaries, if they are lower.
They definitely are more obedient and expect and demand less in (they will not balk at coming to the office) some ways, but expect and demand more in others, like vacation.
I was there for about 5 years and as time went on it felt like we were gradually more and more preferring the the Visa holding employees, and even the managers became more and more Indian.
Everybody and everything tries to work every angle to their advantage. That is the one constant in life. If a business spots an angle, they will use it. I guess we all will, but they seem to have more opportunities to do so.