Unfortunately, not all Russians are against this war, many people don't even know that there's war, because as of now even saying "Stop War" is punishable by 3 years in Prison, distributing non official information about the war is punishable by 15 years in prison. All free media is banned as of now, newspapers closed down so their journalists don't go to prison.

As for protest, if you think there's a lot of military in Ukraine, wait and see how much military is in Russia. There's 400k "internal" army alone that is dedicated to fighting its own people. Putin has created this army after the Ukranian revolution so the same thing doesn't happen here.

In Belarus 95% of people were against Lukashenko and took to streets like wildfire after the rigged election a year ago, did it help? As long as he controls the military protests can only do so much.