What would your ballpark be for that? Not sure how much to negotiate for. I have more than a decade of experience, albeit not a manager.
I’d really suggest asking an employment attorney as they’ll have a good idea what the issue is worth. For example, let’s say you are a protected class and they discriminated against you. That claim and the cost to defend it costs X, if you ask for Y and agree not to pursue them further than you’ll be in good shape assuming Y is within reason to X. If they have a counter claim there would be a reduction in the total amount but still worth settling.
Hopefully that helps you some. Good luck! Sorry you had an issue, it sucks.
On the other hand, you don't want to push that too far. Don't burn bridges with any of the people involved by how you handle this.
As far as concrete estimates of what to ask for - I don't know.