What are you basing any of that on? The seizure of Kiev was Moscow's main aim with the invasion, as it would have led to total victory and the ouster of Zelensky's administration - which is precisely what Putin said the purpose of the invasion was!

Second, the assault on Kyiv was by far the largest commitment in terms of Russian forces. The force was made up of tanks and armored vehicles stacked three abreast that stretched for 64 kilometres (40 mi) and was covered by air defenses and artillery. You don't do that to "pin down" defenders, a full-scale assault is meant to offensively capture territory.

However, due to a tenacious defense, faulty equipment, and incompentent leadership, the assault failed. They were not withdrawn, they were routed! It was only after this point that Russian forces committed to assault Kharkiv, their next major objective.

Last, why would Ukraine be insincere in wanting peace? They are the invaded party, they are the ones who cities are being shelled and civilians being murdered, raped, and abused. Claiming they don't want peace, much like Russia, is asinine on its face.