Putin is no longer trying to preserve infrastructure and will destroy Ukrainian forces with sustained bombardment.
Putin lacks the resources for sustained bombardment.
He had to go to Iran and some say North Korea to replace dwindling or empty stores of drones, rockets and missiles. Putin can’t make them at home because he does not produce all the components required.
The only thing he may have left is artillery shells. But, it is reported that accuracy is degraded by worn out barrels on the guns.