What are some strategic ways to handle a micromanager who is overstepping their role through intimidation and discriminatory tactics without involving HR?

What are some strategic ways to handle a micromanager who is overstepping their role through intimidation and discriminatory tactics without involving HR? *My own manager who I report to, has made it clear through their words and actions that they will not advocate for me and do what's right by standing up to this person, who is their colleague in the same leadership role as them because my manager is scared to step up and also because they're friends outside of work. I've been communicating with my manager to get the situation diffused and resolved so we can all move forward but the pace of action has not been steady. My manager "doesn't know what to do" but I refuse to wait over a week to have a meeting with my manager's colleague who crossed the line with me. All of my communications about this matter have been professional and stating a call to action in the most respectful way. I say all this to say that I know for a fact HR will not be able to help me and provide a safe space for me. HR will be in agreement with this person because they've been employed there for years and this person is flipping the narrative around so that I am being portrayed as the aggressor even though I was the person confronted in the presence of another employee who sat at their desk in silence for the entirety of the incident.

My manager is not willing or equipped to advocate for the employees that report to them against this person who is known to have a negative reputation in the office. It is clear to me that the default mechanism is for this micromanager to bring HR into every situation because they are trying to abuse their power and scare employees into following along with their own narratives and agendas.

I've been at my job for over a year. Ever since my experience at my place of employment has taken a different turn, I've been taking the time educate myself on all of my rights as an employee and all of the employment laws in my state. I truly feel disappointed and more about my experience. I feel like the best thing I can do is seek out support from other departments at my job that do provide safe spaces and document everything so that when I do use my voice to advocate for myself, I have a paper trail to validate everything.

I appreciate anyone who provides any tips or insight on how to navigate this situation. Thank you.