What you need to understand is this.
PTI was in government. The cases against PDM were going smoothly and almost to its natural end.
The PDM always wanted PTI out as the cases against PDM were iron clad and PDM had no way out.
With time there was friction between IK and Bajwa. Establishment wanted to keep the hybrid regime model while IK was not budging. He wanted control of Pakistan’s foreign policy and other domains.
That’s when Bajwa’s and PDM interest converged. IK got hint of this (probably through ISI/Faiz). Bajwa’s meeting Shahbaz without IK’s approval, Bajwa’s ego issues, insecurities of head of state taking the premier role and then the cipher (which was hidden by the Foreign office initially).
And then the day IK was overthrown and the public reaction. IK’s narrative knowing full well public on his side. Add to it PDM only objective was NRO 3, which proved IK correct.
Establishment knows it has miscalculated. But they are in panic and to be honest they don’t know what to do. It’s an unprecedented situation these boomers are facing and have no clue about.
The gist of the cipher was a threat/conspiracy, and US dislike for Pakistan’s relationship with Russia. The details of the cipher do not really matter at this point.