I don't believe Putin cares anything about his human losses. I do believe that he has to be successful or he will be replaced.
I see the map of what Putin has taken in Ukraine. The major Ukraine cities, if not overrun, are surrounded. Right now, though protracted, it's looking like a bloody, messy 4th quarter win coming for Putin.
There was a "press conference" aired in Russia wherein Putin had all of his top advisors sitting in a semi-circle, and he went person by person demanding they gige their "opinion" on invading Ukraine. The fear on their faces was obvious, and when the top intelligence guy kinda waffled on saying "DA!", Putin grilled him for 3-4 minutes - on camera. Replacing him will take a coup, doubt it will come from the party.
Most of the Ukraine cities are not surrounded, certainly not Kyiv. Heavily damaged, yes, especially Mariupol. In fact, yesterday the report was that the Ukraines had actually pushed Russian troops away from Kyiv some 20 miles or so.
My wife and I watched a Ukrainian movie last night called Kruty 1918. A battle raged at a train station where 400 army cadets and 300 students held off 3000 bolshevik troops for a day. There is now a memorial there, not only for the defense but for the 30 or so students the bolsheviks murdered after they took the station. I mention this only because the Russians tried to take and destroy the monument recently, but were driven back leaving over 200 dead in the process - according to the Ukraines.
Interesting article today that the Green Berets have helped the Ukrainians since 2014, training them in small unit and guerrilla tactics. Given the estimated 10k+ Russian dead and thousands of destroyed vehicles, I would say the training helped.
That said, if Putin gets really nervous, well, he is EX-KGB and I would think that almost any action would be do-able on his part. That is where the coup might happen. The Russian .mil has seen how poorly their men and materiel have faired against a small army and an insurgency, and the risk of antagonizing NATO (toothless as it has often been) may be too much. One can only hope. I saw a report where one of the Russian prototype nextgen tanks - a one-off tank - had been knocked out. If they're throwing untried weapons into the battle - with no spares and possible limited training for the crews - they must be scrapping the bottom of the barrel.
BTW, I don't think Putin threw his least trained into this, I think he sent the standing Army in (in various guises), not expecting the violence of the Ukraine resistance nor the speed at which the Russian army depleted itself of men and materiel. Remember 2014 - that is more of what he was expecting, especially with Brandon at the helm here (backed by the ass-kissing Austin and Miley).
What we are seeing is evidence of Russia still suffering after the Soviet collapse, and the fact that the ruble has never really been stable enough to fund significant increases in their military establishment. Thus they were quickly unable to muster a credible threat in spite of all of Putin's blustering. Individually or in small numbers I'm sure the Russians could be a handful. But, damn, the Ukraines sank one of the Russian warships in the Black Sea.