An examination of publicly-reported deaths shows that at least 207 Ryazan ex-cadets have been killed since Russia launched its invasion, a figure that represents around 4.5 percent of graduates over the past decade. Not all deaths are publicly reported
300K losses on 1.2 million active personnel is a quarter.
The well trained officers are a small percentage of the officers in the Russian military and are also deployed to other locations than the fighting in Ukraine. So extrapolating such a small dataset of specialized officers towards the whole of the Russian forces greatly underestimates the death-toll.