It's hard to know what to believe after it came out that fighter pilot story was fake, but the videos I have been seeing have been pretty stark. There seems to be a general trend.
1) Lots of Russian soldiers don't want to fight, and either abandoned the equipment or gave themselves up. One of the POWs said that he was told all they were doing on the border were combat exercises before all of a sudden being told to roll into Ukraine without much of a plan other then to brute force towards Kyiv. None of them thought they were actually going to do anything until the final hour of invasion.
2) The Ukrainians are using guerilla tactics to basically lead the Russians into kill zones, including changing / removing signs so they don't know where they are going, and blowing up their own bridges to prevent the Russians from alternate routes. Once a truck or convoy moves through a zone they basically brutalize them from all angles with gun fire and anti-tank weapons. The worst one I saw was a transport and armored vehicle rolling through a town square only to be obliterated by what sounded like hundreds of machine guns. The transport got stopped almost instantly, one soldier jumped out to try and escape, but was instantly killed after hitting the ground from the amount of bullet spread. The armored vehicle panicked, and while swerving around the road ran over a civilian car with an old woman inside (what the hell was she doing!?) but lucky for her she survived. Never saw what happened to the armored vehicle, or if they escaped or got destroyed too.
Either way it does make that figure seem pretty reasonable, because these transports are often carrying dozens of soldiers. Each convoy getting caught in these kill zones could lead to hundreds dead in a single barrage, since many of the transports are not armored.