The interesting thing here is that this bomber was not destroyed near Ukraine, but rather at a base most of the way to St. Petersburg.
I would have guessed that that would be some of the best-defended airspace in Russia. A drone getting through to there implies some interesting things about the distribution of Russian air defense systems.
Their air defense is spread incredibly thin between Moscow, all the bridges, the supply depos, and all the air force bases. They don't have enough, so they'll keep losing massive amounts of material.