You have all the powers that Putin currently does. Everyone completely loyal to Putin is now loyal to you. Enemies of Putin are enemies of you. Putin no longer exists, and there has been a clean and absolute transfer of power to you. The economic, military, social and political situations are the same as they now are. You are not inhabiting Putin’s body, you are just you. You’re magically transferred to the Kremlin. The world at large doesn’t know your past life, to them you have magically appeared as the new ruler. To everyone who knew you before, you just vanished.
Edit: no one knows your past life YET. They’ll quickly figure it out. You will not lose any support based on your actions in your past life.
As I, Ivan IV, now stand as the undisputed ruler of Russia, my first act shall be to consolidate power by crushing any remaining dissent among the boyars. I will strengthen the central government, expand our territory through conquest, and establish a centralized, autocratic rule to ensure the absolute authority of the Tsar. The people will be brought to heel, and the Orthodox Church will be harnessed to support my reign. Russia will become a vast and powerful empire, feared by all, as I reshape it according to my vision.