I don't think Putin is worried about loss of life of Ukrainian citizens. He is worried about losing soldiers, or more importantly dead soldiers being repatriated on the news. They will cover up civilian casualties or blame them on Ukrainian troops. The only support for this will come from Russia domestically and it is that which he seeks to maintain with this war. Which I'm guessing he hoped would be quick and decisive, avoiding the bloodshed of Russian soldiers that will be his undoing at home.
He should be worried about catastrophic losses like that, it'd be a propaganda coup against him. Small scale killings can be swept under the rug though.
However, as an autocratic state, I wouldn't be surprised if Russian social media was shut down if it was used to spread messages contrary to state propaganda.
Putin just wants to create another puppet-state, same as Belarus. He absolutely doesn't care about the lives of civilians, but ruining the infrastructure is not in his plans (only strategical infrastructure)
