Anyone that worked at those companies would tell you that there is little discretion in how salaries are set for rank-and-file employees. There is certainly abuse, but I don't believe it happens in FAANG companies.

Source: I worked for a FAANG company as an H-1B worker. They "mistreated" me so much that they sponsored a green card for me. Quotes mean sarcasm, just to be clear - it was a chill job with very good work-life balance and I have never felt mistreated.