Look at their today numbers. You can watch them go in real time. It doesn't say how many of them are from sickness and old age vs. the war, but it has to be a huge part of it, right?
https://worldpopulationclock.net/russia-live-population-clock/
Edit:
Rosstat stopped publishing most monthly birth and death data in 2025, so recent figures rest on partial releases and independent estimates