AFAIK it's more of a nudge-theoretic information bubble. Most people will just listen to the news put right in front of them. Russian language independent outlets targeted at Russia exist, but obviously are facing an uphill battle to distribute their stuff there, and if they do get through there's no way for a person to know they're not just a different kind of propaganda. Plus, the version Russian media tells is much more flattering to you, a Russian.
If you're the kind of person who's ends up on Lemmy, you may be willing to learn English and expose yourself to the outside world, however ugly what you find is. Most people are not that savvy, though.