Trying to get the other party to accept your version of events — who's at fault, who deserves credit — is a losing use of negotiating energy. Parties can walk away holding permanently different stories; what actually moves is what can be exchanged and enforced. Fighting for narrative agreement burns leverage on a goal (being believed) that isn't the goal you actually need (a workable deal).
This complements The Friendly No (Firm Disagreement Without Demanding Agreement) (which handles disagreement over a specific claim) by drawing the boundary around what's worth contesting at all: contest facts you need on record, but treat the broader story as something you may never win agreement on, and redirect that energy toward terms.