The fact thousands were on the street DAY 1 protesting this war (knowing they'd be beat and put in prison) and that the first wave of troops were
about assaulting ukrainians says pretty clearly a good number of russian might believe their propaganda, but they don't believe in this war.
Putin will put the blame on the west, he can destroy Ukraine and say "the west did this" like he's Roman Reigns heel character.
But when troops die over a war they don't believe in and the country's economy goes to absolute shyt over the same conflict, I don't think there's any propaganda nor state control that can deal with that level of civil unrest.
Revolutions happen over the most simple shyt. Your pockets hurting and your children/relatives dying is not something that can be justified with "fear of the other" in this particular case. It might be in 5-10 years if the world lets Russia rot in isolation though, that I agree could be a very dangerous consequence of this war.