The argument is about the project timeline. But the actual suffering is not about the project timeline. The actual suffering is about the fact that the timeline is not what was expected — and the mind is in rebellion against the gap between expectation and reality.
The Buddha called this mechanism Upadana — clinging. Not just the desire for pleasant things but the deeper movement of insisting that reality conform to preference. When the unpleasant arrives, clinging produces resistance — and resistance is precisely the mechanism by which the unpleasant becomes suffering rather than merely difficult.
Marcus Aurelius: You have power over your mind, not outside events. Realise this, and you will find strength. The strength he describes is not the strength to change what is already determined. It is the strength to not add the second arrow — the Buddhist image of suffering as two arrows: the first is the painful event itself; the second is the mind's reaction to the event. The first arrow is sometimes unavoidable. The second arrow is always optional.
The question for any conflict: what is the fact I am not accepting? Not the fact that should change — that is legitimate strategic assessment. The fact I am not accepting because I do not want it to be true. That is where the energy is going. And that energy, redirected, is always more useful than the continued war against what is already the case.