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.
According to the travel advisory, that would be Kyrgyzstan, Kazakhstan, Estonia, Georgia, Latvia, Lithuania, Turkmenistan, and Uzbekistan where you can all “exercise normal precautions”.
Would not recommend people to go to the Baltic states in order to use/practice their Russian though. Central Asia is probably the way to go for that purpose.
Armenia is perfectly safe as well and everyone speaks Russian there.