I think that even now, when most Russians have become insane fascists, it is easy for the USA to overcome Putin if they do this in such a way:
1) Declare, that in the case of "Nuclear armageddon" (massive nuclear war), if many Russian missiles will be launched to the USA, USA will launch missiles in retalliation not only to Russia but also to Chine;
2) Declare, that the USA plan to join the war in Ukraine;
3) Declare, that they will stop doing that. either if China will join the sanctions against Russia, or if in Russia a referendum would be pefromed with the suggestion to calcel censorship in the internet and political repressions.
These declarations must be maid as publicly as possible, so that all Russians know them and the nuclear threats of Putin will lower his rating in Russia.
I am sure that Russians will be unable to fight in such a war, because the Russian soldiers will suffer from a cognitive dissonance - what are they fighting for? For prohibiting this referendum?