Copy/paste of comment by u/penelopepnortney:

Some interesting takes from a recent Duran video titled, "Knives out, panic sets it, Zelensky's government purge."

• it was originally reported that Zelensky fired the head prosecutor (comparable to the Attorney General in the US) and head of the SBU but a couple of hours later was the news that they weren't really fired, they had just been suspended, which strongly suggests MAJOR pushback, i.e., that there's a challenge to Zelensky's authority.

• the justification given for the dismissal was treason, the belief that the legal and security/intelligence services had been infiltrated and were responsible for Kherson falling under Russian control, which happened months ago. This isn't believable, it looks more like an internal crisis, a pre-emptive strike on Zelensky's part because he fears a general coup against him is in the works.

• the fact that the AG is involved suggests he's worried about a domestic political challenge, and it's not difficult to understand why - the military situation is in disastrous state with Lugansk lost and Donetsk in the process of being lost, and the Kherson counter-offensive turning into a piece of theater and mirage; the million man army has vanished into the mist; Kharkiv is now in danger, etc.

• Everything suggests that the battle is being played out not in Kiev but in Washington, where some factions are exasperated by Zelensky's incompetence and his making one bad call after another; they probably sense the anger and disillusionment with him in Kiev and are thinking to find someone more competent to replace him.

• having the incompetent Zelensky in charge has been to the Russians' advantage so they're the least likely of all the players to try and orchestrate his replacement. OTOH, the Ukrainian position is so deteriorated at this point that it's unlikely to make a difference.

• changing the leadership would require ignoring Ukraine's Constitution and would further erode the credibility of the government in the eyes of Ukrainians and the rest of the world, so such an action may do more harm than good (parallels to the US-endorsed overthrow of the South Vietnamese president in 1963).

• Replacement candidates may include General Zaluzhnyi, commander of Ukraine's armed forces, or former president Poroschenko who, coincidentally, is in London at the moment.

NOTE: recalling Robert Barnes' adage about "confession by projection" - i.e., what these sociopaths accuse others of doing is what they themselves have done or plan to do - Zelensky should interpret Jake Sullivan's remarks as evidence of what that faction of the USG is planning to do.