The Soviet doctrine, as far as I know, is: First to suppress the enemy with superior firepower and then to destroy it by encircling it with low-trained but large numbers of soldiers. The operation of this system depends entirely on the very good functioning of the army logistics.
Their disdain for guided munitions and finding them both mostly unnecessary and excessively expensive prepared the end for the Russians.
First, their logistics collapsed. Because they relied so much on unguided shells, they needed an excessive amount of unguided shells. This put an enormous strain on the logistics system. Ukraine's actions were the spice of the matter.
Second, the Russian artillery was destroyed without a fight because of the NATO systems, which have longer ranges than the Russian artillery systems and which make precise shots.
The fact that they considered guided munitions mostly unnecessary also showed that they were an immoral society that didn't care about the lives of civilians!
The entire Soviet Doctrine was built based on what DOD describe as Area Targeting. They use their troop and resource to saturate an area of target, instead of what we do in the west and what the Ukrainian is currently doing, which is to seek weak point and attack your enemy center of gravity. All their unit are build based on that, and all our unit are build base on our own doctrine. That's why they deploy their troop in a bloc of Battalion, we deploy in companies and sometime even platoons.
I wouldn't say they disdain PGM, rather they don't really trust it or use it according to their doctrine, because you need to take down the entire area, and swamp your troop in, it's really pointless to seek weak point because you are going to attack all of them anyway, which mean they really don't need PGM that much the way they operate.
The thing is, Russia military knows their school of thought were out of date. They were desperate to change and that what 2008 Military reform (or 2015, I don't remember which one) is for. But then that mean you will need to change the entire structure, which mean cutting force that you don't use and changing or redirecting contract to new supplier which is going to hurt the upper echelon because they are all in bed with the supplier in Russia.
So when one thing fail, it all started to fall apart, and that started from Russia trying to bite more than they can chew. They started 3 lines of axis for general attack when they are trying to take every town and every city in between, This mean they would need to constantly supply their military for that month they are trying to do that, which they can't because that's impossible in military term, and they aren't used to splitting their force up like that, Bear in mind almost all war Russia fought before Ukraine was one directional, and with local support. Unlike in Ukraine.
Even US when we attacked Iraq using a 3 pronged approach (Marine from South, 3rd ID go around and attack Baghdad direct and Airborne taking Northern Iraq) we don't try to take every town because we know we can't as you will depleted your force and strain your supply line because once you used up your supply, your truck will need to go back all the way to staging point, and nobody can have a "Wagon" that big and that long.
The reason why NATO system works is because we pin point their C&C and pin point target with high priority (communication hub, staging point, ammo depot) all those would affect how the enemy fight, and it will compound the problem simply because the size of Russian unit.