This quote from the article shows that the headline is, at best, very misleading:
Back in December, US officials estimated that Russia had sustained at least 315,000 casualties, almost 90 percent of its original invading force.
In plain English:
* Putin's February 2022 invasion force was ~350K troops;
* In the
nearly 2 years from that time to December 2023, Russia had suffered ~315K
casualties;
* The ~315K casualties is cumulative over a long time period, not a brief time period as the headline suggests;
* "Casualties" includes those wounded and captured; ~315K troops were not "slaughtered";
* Very obviously, Russia has and is substantially reinforced their invading forces; the effects of the losses of troops and equipment have corresponding losses in Ukraine, but does mean Russian plans to invade Moldova, the Balkans countries, and Poland have been severely disrupted.