Ukraine makes the claim on the eleventh day of the Russian invasion
www.independent.co.uk
Obviously can take this with a massive pinch of salt, but according to Ukraine, Russia has lost 11,000 soldiers in the first 11 days.
I'm sure this is exaggerated, but if true, Russia is in 11 days quite close to approaching the number of casualties the USSR suffered in 10 years in Afghanistan (14,500). Gives you some sense of the scale, and as Russia is a much smaller population than the Soviet Union, the loss to Russian society is proportionately much higher too.
They have already lost more tanks, helicopters and aircraft than they lost in Afghanistan too, which does certainly seem plausible.