[VA]When is taking action against unethical leadership a bad idea?

I am employed in with a for profit mental health center. This is a situation that is breeding ground for ethical dilemma and whenever a conflict between what's best for client, or best for business and business always wins sometimes causing a lot of difficulty for staff. The person making decisions is often not even discreet in these matters and this has lead to multiple morale issues and higher than usua turnover.
Decisions made relating to staff are equally problematic ranging from abruptly cutting hours ( some ppl have moved from other states based on offer of full time hours (we are all hourly non exempt). It is opposite for clinical staff who work 60 hour plus weeks often refused overtime. Employees have filed complaints with HR, regulatory board, compliance, but most of them are young and this is their first job so they just stay and fall in line and complain to everyone else. Either way, no relief has come from grievances filed thus far. At one point I met with this leader and told her respectfully that I felt unsupported and unheard throughout my time here. Two days later I was summoned to a meeting where I was told that anonymous staff members had complained about me but their confidentiality had to be respected so they could not provide me with context, details or any information and I had no way to take action on this verbal warning. From that point on, everything I say or do has been misinterpreted as being negative or challenging and she often writes formal emails to paper my hr file. I've been interrogated after talking to coworkers one on one which is not avoidable in this work so she has been successful in isolating me after telling me that anonymous coworkers were raising concerns but didn't feel safe telling me themselves. I am 59 years old and I can't imagine anyone being so threatened to pull me up on something that they would need to seek out leadership. Also unclear on whether it was one person or ten people. I should say she pulled exact tactic on a colleague prior to me and that colleague withdrew completely from all of us. It is certain that this leader is comfortable with divide and conquer and it worked on me too for a time. I should also add that she is aware that this issue has been brought to HR and has likely gone back to document some "evidence" of these coworker complaints. After not talking to my coworkers for a time they began to approach asking what was wrong with me. When I explained they seemed genuinely befuddled at the whole thing and denied going to management about me. One person said that they called her into their office and asked personal and pressing questions about me under the pretext of being concerned about me. I have been of late under constant scrutiny, as she waits for me say or do anything that might infect the positive work environment( which had not been negative since my first day there) For my anonymous complaints a performance verbal was delivered. I am a resident so getting a different job would have been impractical at the time. I did file a detailed complaint with HR but saw no result despite HR telling me they were very concerned at my allegations. Since then I invested a good deal of effort in keeping my neck turned in an effort to keep the peace and stay employed. I was recently hospitalized with RSV And since then it has been unbearable. Ultimately I made the decision to move on though not immediately. I informed my clinical supervisor of my intent and was summoned to another HR meeting but was told the HR person couldn't be present so my directors supervisor would take her place. ??This person is not an HR person and had proven to be unsympathetic to any of our concerns. This meeting It was supposed to be informational about resignation process only but my director informed I was to be placed on corrective action (final warning) for not maintaining a positive environment because I told a colleague if my plan. Later in the meeting I was told it was also because of complaints from colleagues and a client, but sorry that's all they could say. I was told I had 2 hours to sign the form and this was not negotiable. I've never been on any type of corrective action so I assumed this was an ultimatum and no HR rep was available to help me. I signed the form. I had lost 25 lbs in 4 weeks and was struggling to focus at work so gave 4 weeks notice immediately.
Since then I have heard from former employees telling me they experienced similar treatment. Since then, same director has been harassing a colleague who had filed a compliance grievance and asking her to resign or take a position at another location. I have filed a compliance report and they responded that they were investigating I but am tempted to pull it in case because I have seen no whistleblower act is going to help me if they add some commentary to a reference that could leave me unemployed indefinitely. I also have a license to protect. I implicated director, her supervisor and HR for taking no action in the report. This is a smallish industry here so this seems like it could be a real threat as I would never know and if I did would have no recourse. It's hard to walk away like everyone before me and let this person continue this way. But I am wondering now if it's too late to cancel my complaint. I did it anonymously but they will certainly know it is me because of the details. The other person who is on a corrective action for the exact same reasons is so afraid of retaliation she will never take action.