My manager sucks her thumb!

Hello i need some advice and wonder if IABU?

I work for a small ish company in a low paid office type role. In my department theres me, another lady and our manager.

My problem is with my manager.

She sucks her thumb at her desk...ive seen her do it numerous times and even the smacking sound when the thumb comes back out 🤮

She has a very bad temper. To the point where i feel i am walking on eggshells when shes there. Constantly huffing and puffing, for god sake this and that. Shes kicked the photocopier and actually sat pulling her hair out whilst shaking in anger. Pretty much like the way a child would behave.

If she has any criticism at all come her way she will cry at her desk. She also cries regularly because shes single/cant afford abything etc which is sad but it makes everyone else feel awkward and shes completely unprofessional.
This is why ive always never been able to actually say something to her as it would probably come out wrong and i would say things that really upset her which is what i dont want.

I feel for her as i know she has a lot on in her personal life and i can imagine it mustnt be nice.
But shes always the victim. We are all going through things, i have a close family member going through an awful disease and im not bringing that into work so i dont see why my manager should.

I have been working at my place for nearly 2 years and i do love my job. I just cant stand this behaviour. Theres a lot more but this is a good start.
My colleague left recently because of her.
Its got to the point where i am so unhappy there i feel like ringing in sick which i dont actually want to do.
Ive looked for other jobs but no luck yet. But i also dont see why i should have to put up with this and move jobs because of it.

Ive had a couple of conversations with higher management about her and her anger but nothing really gets done about it.

Im feeling ready to actually ask for it all to be a proper meeting and recorded on paper so they have to actually do something. I just dont want the repercussions of her finding out i have complained and the tension/awkwardness between us.

Please if anyone has any advice of how i go about it i would very much appreciate it.
This is making me so unhappy and i just want to get it sorted.

Thank you.