There are other incentives than caring about people to not level Kiev. First is the optics. This isnt like a drone blowing up afghani villagers without cell phones on the butthole of the planet. This is pretty much a first world country with phones everywhere. The Russians would be seen as blood thirsty psychos in real time. If Putin starts blatantly targeting civilians, the odds of the west setting up a no fly zone goes way up. He'd also end up isolating himself from everyone I doubt China would even approve of that. The temptation to make themselves look good, and the threat of being sanctioned for enabling Russia would go up too. Secondary is the cost to repair the infrastructure they destroy. Russia has to do this by the book, and they have to win a propaganda war to be able to even take the energy resources they are actually fighting for to market after all this is done. I really doubt Putin gives a shit about anyone's life.