Russia has lost 500,000 men, killed and injured. All the Ruskies said that Russia would take Ukraine in 30 days. They would lose 500,000 more men before they do.
The BBC and Mediazone can only confirm 40,000 or so Russian causalities. And, even if they can't find information on all the causalities, there is no way the total number is even close to 100,000.
Russian casualties in Ukraine. Mediazona count, updated 40,599
Russian casualties corroborated by publicly available data as of 29 December