agents of influence
Currently active Russian government politicians (whose children study in the West and who have fat bank accounts there) are West's agent's of influence? Interesting theory.
But again, let's assume your theory is true - Putin remains in power and Russia is isolated and ignored by every decent country in the world. Russian diplomats are expelled and foreign embassies in Moscow are closed. Russia moves into the North Korean system of
Juche (self-reliance). Tons of money are lost, people are inevitably poorer and the country weaker, Nord Stream 2 is never opened, Nord Stream 1 is closed, Europe is forced to reevaluate its energy policies without the use of Russian sources (it hurts initially, but eventually new sources are secured). Also, NATO is significantly strenghtened - more money is spent on weapons and research (a race that Russia can never win with the West - you tried in the past and that's how USSR fell). As for the conquered Ukraine, Ukrainians are ruthless if need be (we know that from history), so the terror that hits Russia daily makes the Israeli-Palestinian conflict look like kindergarten fun.
The losses for Russia in this scenario are immense. The gains? Some parts of Ukrainian territory (perhaps even the whole of Ukraine), final subduing of Belarus... I don't know what else... maybe better relations with China... maybe... but Russia is economic and population dwarf compared to China so they will never treat you as equal partners.
To sum up, I still don't see how Putin decided that the gains/losses balance is in favour of Russia.