The Institute of Study of War (ISW) tells that Russia wastes its power in meaningless battles.

Su-25 "Frogfoot"

Why Russians are wasting their power? The fact is that two things can explain why Russians are fighting in meaningless areas, wasting their power and causing casualties. The first thing is that the Russian military is following the original battle plan without caring about casualties. And Russians might think that some area is important to them. But Ukrainians or Western observers think that the areas have no meaning in the war. 

There is the possibility that the Russian military makes its casualties on purpose. The Russian government promised over 8000 euros price for recruiting to the war. And if those soldiers die, they must not pay that money. But another reason why Russian waste its power in meaningless areas like small towns can be in defense tactics of the Ukrainian army. There is a possibility that the Ukrainian army makes "unnecessary-looking" hard resistance in the small towns and countryside.

That kind of tactic when the defender wants to make a series of resistance battles is effective against an army that uses massive firepower. If the Ukrainian military will try to hit Russian troops in one battle by using the tactics where a large group of troops faces the Russians in one solution battle. That causes the ultimate loss for Ukrainians. 

The major part of the Russian tactics is maybe that the Russian main force faces the Ukrainian main forces in an open field battle. In that battle, Russians would use the TOS- mortars, thermobaric explosives, and other kinds of stuff. The idea is that if the Ukrainians are using the fixed combat positions the Russian recon planes will locate those positions. And then the defender will be bombed away by using air force and heavy artillery. 

Attacks before a big solution battle are meant to cause casualties for the attacker and leave it without ammunition or some systems. The loss of tanks, heavy artillery, and mortars force Russians to order those systems from Russia. 

And spend its force. In this kind of tactic, the idea is that the defender will destroy some vehicles and other units. And then step backward. If the defender can destroy the force of the attacker before the main battle, it cannot use all its weapons that are meant for that battle. The Russian tactics like massive, but non-accurate firepower favors the single battle tactics. 

The idea is that the Russian military will crush the enemy in one single battle where it can use its mortars and all its firepower. So one of the best counter-tactic is to try to force the enemy into warfare where the attacker must use unduly firepower. So this is one variation of the "Hit and run" tactics. 

When Russian TOS rocket launchers and heavy artillery comes into place those systems will target HiMARS or Ukrainian Howitzers. And then those systems are destroyed. Also, combat helicopters and attack aircraft can destroy convoys, especially at night time. And those attacks destroy the combat vehicles or support. And if the fuel trucks or ammunition carriers are destroyed the troops are left without equipment. And that thing slows the advancing. 

Image: https://worldinconflict.fandom.com/wiki/Su-25_Frogfoot