I can't speak for Putin, but MAGA is a cult of personality. Once HitlerPig assumes room temperature, there will be a vicious battle for leadership, and at least half of the MAGA Morons will drop out without their divine leader to follow. Its very likely they will pivot to making him a religious figure.

The traditional GOP will try to recapture their hegemony over the party, and the Sociopathic Oligarchs will wage a war to keep and expand their influence. They will all try to float a new leader, and we can expect HitlerPig Jr to make a big attempt, but he'll be recieved the same way as Frank Sinatra Jr - with a yawn. Anyone else will be accepted even less.

I hope the battle for control of the party will result in internecine violence, so the Dems can regain power, and use the crimes and violence of the MAGAs to crush them, and purge them from government and society.