I think you're using a non-military definition of feint. You seem to be treating a feint as a fake attack. A feint is a real attack that is designed to draw defensive forces towards it.

"A feint attack is designed to draw defensive action towards the point under assault. It is usually used as a diversion to force the enemy to concentrate more manpower in a given area, to weaken the opposing force in another area.[2] Unlike a related diversionary maneuver, the demonstration, a feint involves actual contact with the enemy. " -Wikipedia

Russia attacked Kiev and that meant Ukrainian reinforcements had to be sent there instead of to the south or east. I don't know what Russia intended exactly but it looks like a feint from here. It could have turned into a full siege of Kiev if Russia had reinforced that front instead of the others and in that case either the Donbas or Kherson attacks would have been feints. This is pretty standard Soviet Deep Battle doctrine, you attack on multiple fronts and reinforce the ones that breakthrough, the attacks that don't succeed still function to pin enemy forces into place. There's no reason a feint can't be turned into a full attack and Soviet doctrine didn't make a real distinction between them.

With the clarity of hindsight it seems that Russia expected to rapidly advance on the capital and force conciliation but once the west began arming Ukraine and those overextended flanks became easy targets for new man portable AT weaponry, the advance became an unsustainable position and Russia was forced to retreat and reorganize. Fundamentally changing how they would prosecute this war

I think you're basically exactly correct here. Russia attacked Kiev for both political and military reasons, decided not to reinforce the area, and then pulled back when defending it became too costly. I think the disagreement is largely on the definition of a feint.

That’s like calling a punch I whiffed on a feint because it didn’t hit you

In military terms that would be called a shaping operation. (I'm only sort of joking).

It's far from impossible for major military operations to have more than one objective, even mutually exclusive ones in the case of the failure of plan A, then plan B, then plan C, etc

it might have gone: "Well, we'll march on Kiev and see if we can take the city quickly. If we can't, and we probably won't, then we can at least use the pressure to form a peace deal. If that also fails, then we have distracted Ukrainian forces in the Donbass while we situate our men there and supply the militias."

I feel like if the Russian planning stopped at plan A or plan B, and they didn't expect to have to fight for Donbass territory because Ukraine would sue for peace or collapse, then we wouldn't have seen, for example, the battle for Mariupol, which began in the first week of the war, especially given how hard urban combat is (and proved to be in Mariupol's case)