Given that their only source of info is state media, I don't think it is realistic to expect uprising

Why do you think their only source of info is state media? Do you think Russians don't have internet, social networks, group chats?

All in all, on average, primary source of info. Afaik, a lot of works goes into controlling which parts of internet are well accessible and which are not. The social networks and group chats are amplifier of what you see elsewhere. They don't bring new information from outside into debate. They are also reflection of what you consider appropriate or safe to share. And with new criminalization of "disinformation about war", it will be less.

And right now, as far as Russian official version is, afaik, Ukranians are nazi child killers and Russia is there to denazify and protect regions of it.

Moreover, ousting Putin requires more then unhappy disagreeing populace. It requires either super weak regime or internal coup of powerful players. Regime is not weak currently.

People still remember Chechnya and Afghanistan, so I think they expect to have to use unofficial sources for certain kinds of information, like getting information about their dead or missing relatives. I guess we'll see what happens when the coffins start coming back.

Putin's regime wouldn't be the first to fall over a failed war.

In the USA, there is nothing stopping you from going to learn all the pro-Trump, anti-vax, anti-mask propaganda you want, yet millions of people do not.

What makes you think it's any easier for someone to leave their filter bubble in Russia, where the consequences aren't just losing your job and social ingroup, but also being kidnapped, tortured, and being found dead in a ditch five years from now?

Some must see planes turning around, body bags coming home, ships not leaving port, the stock market staying closed for three days straight, friends withdrawing cash, family at sanctioned companies afraid of losing their jobs, etc. and know that something is up.

I don’t think everyone is brainwashed by state media, some just ignore it or tolerate it to stay out of trouble.

I don’t think a civil uprising is likely though due to Russia’s police, military, legal system and covert ops that are willing to dramatically intimidate or eliminate political threats.

Any uprising is going to come from generals sick of bombing civilians or oligarchs sick of losing money IMO.

Did they have truthful media in 1917?

Like, who exactly?

If you mean Russia, they had years of internal violence behind them. They had well established revolutionary movements and terror groups acting inside on top of it even before WWI. And the regime was weak and forced to do concessions already in run up to WWI and even weaker by end of it. They were doing reforms, too little too late, but they were doing them because internal pressure was strong for years.

That revolution did not came out of nowhere. Plus, the population was literally hungry and desperate to large extend. And plus, it was followed by major civil war of like 5 sides competing for power.

Utter speculation on my part, but I see this as both a weakness and a strength for Putin. On one hand, as long as the government and whoever controls what goes out on state media are on his side it helps Putin. If, however, that control breaks down and the people in those positions lose confidence in Putin than the leverage reverses and they can easily use their media in the opposite direction.