In order to enter Russia they will need a negative Coronavirus test made not earlier than 48 hours before the arrival. We also recommend it to be translated to Russian although this is not an official requirement.
Regarding the other borders we expect that Russia will soon open borders with the US, however, it will take at least until mid September for Russia to open the border with EU as the rate of infections is 3 times higher than in the EU and the borders are opened only on the basis of reciprocity.
If you are a US or an EU citizen perhaps you could fly into Russia through UK or Turkey provided you have a negative Coronavirus test but we will only find out if this route really works after we get the first positive reports of the people who actually managed to travel this way.
Note, that the Russian visa centers are opened in many EU countries and in UK from the end of June, so you might be able to get the visa and enter using the routes above.