Management is firing those who go to HR. (TX)

Location: Texas

HR just fired a beloved manager for speaking out against our general manager. GM is having an affair within his department and has been reported for sexual misconduct and harassment of his employees multiple times now.

Those that gave reported him have gotten cut hours, or very ominous meetings along the lines of “you’re going down the wrong path.”

Is there literally anything we as a staff can do about this? He was supposed to be fired within 30 days of his affair going public given corporate policy. Is the only move going to corporate? Anything we can do about our manager who was wrongfully fired?