Intelligence ain't Tom Clancy, Mitch Rapp, or Jack Carr novels. More than one thing can be true. If you think Putin is rational, stop, If you think Zellensky is rational, stop. They have both been backed into a corner and both are irrational right now. Rational men don't make some of the decisions they have made.
Who bombed this chick to death (when in fact it was supposed to be her daddy)? Don't know. Intra-Russian? If so, why? He and Putin were BFFs. But he was an advisor, and no threat to Putin. So anti-Putin actor? Why? Destabilize Putin's decision-making? We know that a LOT of Russians do not support him, and a lot of those Russians have money and opportunity.
Zellensky/Ukraine actors? Why? Well, they DO have an axe to grind. They have motive. Do they have means and opportunity? Don't know.
CIA? Why? Destabilize Putin's decision-making? Make it look like it's someone else?
There could be other bad guys out there we don't know.
Occam's Razor and all, my bet is on Ukraine, or intra-Russian actor.