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.
Afaik it’s somewhat frowned upon in Baltic societies since the Russian war in Ukraine. You’ll probably find some people who’ll happily speak Russian with you, but others might judge you for speaking Russian but not their national language.