> extremely aggressive and borderline abusive behaviour
> In the beginning we we all agreed not to take anything personally and to let it just roll off the back.
Could you have done something differently here?
> We agreed to tighten up our processes and try to avoid confrontations by being super proactive with all our work
What does proactive mean in this sense? That it met client's expectations, or that it tried to pre-empt them, or something else?
> Ordinarily, we would have dropped the client by now and refused to put up with the end-justifies-the-means tactics
Tactics such as...?
> we're coming close to the launch date, and it's getting worse as more pressure mounts.
Where is this pressure coming from? Is it coming from you and your direct managers too?
> This is a very high profile project that stands to disrupt its market.
Is this what you tell your team? If so, that might answer the last question!
> It's exciting for them and us.
That sounds really positive. Does that mean there's a way to share that excitement?
I don't mean to be accusatory, I think this is important to explore if you want a decent answer without the confirmation bias.