The title is yours. The signing is done. The work has started. And the operating model of the room you stepped into is not the one that produced the leader you have been. The decisions move differently. The cadence runs slower. The chain of escalation is murkier. The political signal you used to read in your prior role is not the political signal that runs the room now.
You did not have a translation problem the day you walked in. You have one now.
The first ninety days at altitude either lock the credibility window open or close it for the year that follows. Nobody hands you the operating system for that window. You build it under pressure, on the job, while the room watches.