Apparently you are in an information bubble, captivated by delusions and an abundance of fakes. Russian troops are acting primarily for reasons of expediency. Activity in the northern direction played a role in the initial phase of the operation. To storm a city of three million with a limited contingent of forces is madness. Plus, any agreement signed under pressure is legally null and void, so reducing the pressure on Kyiv is now quite reasonable. This will not help the regular army of Ukraine (go to what is left of it) near the Donbass.