If Russia had actually wanted Kyiv, it would have had set up collaborators and weighed all its offensive power to it. They did not, the units there were not reinforced, they made no actual attempts to close pockets, or even get the few who collaborated out, leaving them at the mercy of Azov. Their job was to draw all the UkA Reserves north, destroy the Main Depots, and Repair Shops of UkA, and do so long enough for Izium to be breached. They accomplished that, successfully broke contact, and redeployed south. UkA was unable to pursue and its famed KORD units largely dropped off the scene after the 2nd Week where as in the first week they were constantly posting social media bits. That's because they got annihilated and were unable to report the withdrawal or harass it. It took Azov 4 days from Russia abandoning Bucha to them reaching it, because the transport networks and logistical support is shot.
Compare to the south where Collaborators were placed in governing control, civil administration is being coopted and they are trying to set up a civil police force to enforce civil laws. These units also have victory banners with them unlike in the North around Kyiv.
This should have clued everyone in from the start what the real plan was. Russia never expected Kyiv to fall, and would have been surprised if it had. They likely never expected Kherson to fall either, but ran with it as it made the Odessa Feint last far longer than they had hoped it would. But its main thrust was for the Sea of Azov and Mariupol which is in the bag and opens the way for the Donbass battle to begin. Victory here, pushes Ukraine into an economic and demographic death spiral they won't recover from.