Hello @Shelz
Ditto on what @MaddieM has offered in the strategies to take and considering what Fairwork has available with advice and advocacy. (I've added a couple more links)
Sounds like the HR dept/person's function is strictly ornamental. The HR will be taking their directions from a CEO and do you know if HR has taken your concerns to top management. Next time you could bypass HR completely after you've had a chat to someone from Fairwork.
A CEO who dismisses a toxic workplace culture of harrassement often has outdated beliefs such as: if you can't stand the heat get out of the kitchen or survival of the fittest. We tell ourselves all the usual things : ignore it and they'll go away; rise above it; be the bigger person; toughen up buttercup; grow a thicker skin; get a hide like a rhino.....and, in a nutshell, you're beating up on yourself. Detach from that mindf* as that is where the contagion of workplace harrassement starts to drag you down.
Workplace bullies who are facilitated and protected by management count on industrious and conscientious employees to perform, as you describe, the work of three - for the wages of one. It's an old master/slave mindset that depends on the bullied 'slave' fearing retribution if they speak up, fearing termination of employment, and the bully-boy 'masters' hope you'll figure out your place in the pecking-order; that you'll sit down, be quiet and stop rocking the boat; stop blowing the whistle. And the timeless classic: Go along to get along.
They are so scared of you. Keep standing up for yourself. Keep advocating for your rights, as a human being, to be treated respectfully and for your productivity to be valued. You are not alone @Shelz - this is an entrenched problem across every workplace and industry and, I wager, there are others in your workplace who feel just as harried and have been beaten down. It is common for workers to go ...ah, it's not worth it, they're not worth it. Admittedly, you do have to pick your battles. Anytime you go in to bat for your own wellbeing and safety @Shelz you are sending a big message, you are saying to everybody: I AM WORTH IT. I VALUE MYSELF.
You're a scary dude....you know that? I'd pick you first for my team.
Are you a dues-paying member of a Union - call your rep. If there is no union in your workplace - start one, become the rep.
From my own experience, the worst harrassement I endured, was in a workplace where the staff noticeboard in the canteen was plastered with posters and literature, heaps of it, from the "Speak Up" campaign (circa 2003-2008)
When push came to shove, the company, didn't walk the talk. They were obliged to display the literature in a prominent place for their employees, to not do would have attracted a penalty from the staff unions.
https://www.safeworkaustralia.gov.au/bullying
https://toughnickel.com/business/When-You-Are-Bullied-At-Work