I can only speak as a US Citizen who visited Russia. My fellow Americans said similar things (that I would be arrested or at the very least treated poorly) but nothing of the sort happened. Everything and everyone were great. I was in a big city, though. My advice would be to not talk politics or to risk offending their sensibilities. Don't discuss things such as WWII, Polish history, Russian history as it related to politics or war, Polish politics, Russian politics, the Special Military Operation, criticizing their leader, etc., as these things can elicit strong feelings from Russians and having a differing viewpoint might cause offense to them. Even if they say it, don't agree with them because they often think that nobody is allowed to criticize Russia except for Russians.