Although I’ll say the Russians are improving. The problem is that their logistics is only capable of keeping their army supplied up to the Dnipro River.
Also, the slow pace is favorable to Russia. Slowly grinding forward, running out the clock, it’s a good way to be in a good position when Zelinsky gets overthrown or assassinated. And Russia has a little incentive to conclude a cease-fire right now. That’s the dream of DC and London, but Russia knows the minute such a cease-fire is concluded with a DMZ, rump Ukraine will be flooded with western advisors, soldiers, and NATO, or NATO light type status. Squadrons of airplanes missiles, etc. But they also know that cannot happen as long as the war grinds on. Russia has the incentive to keep it going
At this point, the option for Ukraine to stop the war is the denotes of fire, and declare neutrality and for NATO to leave Ukraine.