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.
Pull back from Ukraine, Crimea, and Georgia, and negotiate an immediate ceasefire.
Call as many political scientists and scholars as possible and get their advice on how the fuck I can design a reformed system of democratic governance that is robust enough to withstand the inevitable attempts to undermine and corrupt it.
Find the multitude of stashed billions from the various oligarchs and seize it, use the money to invest in overhauling Russian society--improving infrastructure and education, improving the standard of living, etc.
Yeah, people forget that tyrants never stand on their own. They are propped up by a complex system of corruption that benefits from the tyrant's decisions. They will defend this system and the head authoritarian. Not out of love, devotion or loyalty, but to protect their own sources of ill gains. Just like a Mafia, it holds up on a shared complicity of its members on the crimes being committed. This is why generals force low level officers to witness the violations and tortures, and corrupt politicians tie in their underlings in the money laundering schemes. If everyone has something to lose, then everyone conspires to keep the corrupt system going.
Yeah, it's a fantasy, and an extremely off-the-cuff, low-detail, wouldn't-it-be-nice-if list. In reality, I'd probably either shut up and change absolutely nothing while I figure out the power structures, or I'd just work out a payoff to quietly step down and leave without a fuss.
What, asking experts who have studied a topic and has forgotten more about systems of governance and effective anti corruption efforts than I'll ever know is somehow bad now? The fuck?