Except the mistake or maybe feint towards Kiev, the war has been fought in territory that mostly Russians or very Russian Ukrainians are living in. So the Russian forces have not gone all out. Trying to lessen civilian deaths and destruction of infrastructure.
The Russians consider that this will become Russian territory if this ever ends that way. So don’t burn it all down.
They also hope for an eventual cease fire and negotiation that will end with a neutral Ukraine. So again, try and be a little bit nice, as far as war will allow.
No idea if this will happen. But it is why the war progresses so slowly.
The Ukraine forces have done very well in spite of the limitations they face. But they did not face a full on full force Russian attack.
I hope it comes to an end as soon as possible. I doubt the result will be any best case for anyone involved.