There is huge difference in accuracy between a Russian and a western artillery cannon.
At least in 2022 it was commonly estimated that in order to hit a specific target, you need to shoot about ten times as many artillery rounds with a Russian cannon as you would with a western cannon.
Of course, if you don't have a specific target, the accuracy doesn't really matter. The Russian artillery rounds are very useful for carpet bombing a city, but not for any actual military use. And when you're comparing the efficiency of armed forces, actually only the military uses are relevant. For that use, you can use a multiplier of 10. 25 000 western shells have about the same battlefield impact as 250 000 Russian shells.
Then remember that each time you fire a shell, it causes wear and tear in the cannon. That means, the Russian cannons get ten times as much wear and tear as western cannons. Atop them being of a much lower quality. The Russia uses a lot of shells for obliterating Ukrainian cities. Ukraine does not do anything similar. That skews the numbers even more yet.
I believe the only reason the Russia is continuing its war now is what comes after.
It has about 700 000 living soldiers that have been specifically trained to blindly use violence against everything that moves or doesn't move, and to be completely okay with all forms of sexual violence, regardless of age or anything. They have been trained to rob and pillage. Now, once the war ends, those 700 000 will return home.
In the end of 1980's, USSR retreated from Afghanistan, and about 90 000 soldiers returned home. They had a similar training, and the results for the society were horrendous. Yet, the current training has been even more inhumane. And now the Russia has about half the population of USSR of 1989. Which means that the effect of one returning soldier is about doubled.
Those 90 000 veterans of the war in Afghanistan were one of the biggest reason for USSR collapsing, and they were the main reason for 1990's being such a traumatizing hellscape for the Russia. Now, 700 000 will return. And because of the population difference, their effect is the same as if 1 400 000 veterans had returned to USSR instead of the 90 000 that did.
And: At the same time, the Russian economy will be absolutely gutted. There will be a huge amount of unemployment. All the same pieces that caused Russians to get very strongly collectively traumatized by their 1990's will be present again, but now about a magnitude worse. The difference between 1 400 000 and 90 000 is 15-fold. If you take the 1990's mafia violence in the Russia and multiply that by whopping 15, you get the 2030's of the Russia as a result.
As much as the Russia is suffering from this war, it's nothing compared to what will happen once their soldiers return home. Every day that keeps the soldiers away from home is a day more without hell having broken loose for them.
I believe their only goal is to prolong the war as long as possible.