Considering Russian is not only spoken in Russia but also in Kyrgyzstan, Kazakhstan, Belarus, Azerbaijan, Armenia, Estonia, Georgia, Latvia, Lithuania, Moldova, Tajikistan, Turkmenistan, Ukraine, and Uzbekistan, what would be the safest country to travel to where you can speak Russian? Probably not Russia or Ukraine because of the war but yeah.
Estonia is like an extension of Finland (although using Russian there might be hard for the same reason). Kazakhstan has a good rep.
Moldova, Georgia and Armenia have fighting or unrest. Azerbaijan too although they kind of won, and Belarus is party to the whole Russia/Ukraine thing. Turkmenistan has a bad rep for other reasons and is hard to legally get into.
I know less about the other Baltics and 'stans from a safety perspective, although presumably the Baltics are similar to other poor areas of the EU.