Russia has basically shifted to their old doctrine of using an overwhelming volume of basic artillery shells, which allowed them to capture Avdiivka with losses estimated to be 3 Russian casualties to every Ukrainian. They are maintaining this not with having built new manufacturing capacity, they simply are running their existing factories non-stop with three shifts instead of one. Even like this, they can only manufacture enough shells to keep this volume up for 2-3 more months (maybe the Chinese aid they get helps with that?).
On the other hand, the EU and the US has been building factories for artillery shell manufacturing that will ramp up by the end of this year to March 2025 to the point where they will be making as many 155mm shells as the Russians make 152mm. The Russians will not be able to keep up, for that, they would have had to start building factories months ago, which would be obvious on satellite photos.
On the other hand, Russia is ironically having a problem with artillery guns, with their fleet having gone from 80% self-propelled to 80% towed, which is not a good thing in the age of good counter-artillery. Even worse, old WWII D-10 guns are popping up all too often, with ranges of up to 10km, and abysmal accuracy. These are not good enough to outrange better drones even, and eat more shells to get the same results, taking away from the shell advantage.
Point is, right now it’s not even like 1942 against Germany, it’s more like 1916, everything is up in the air. Russia’s path to victory is to keep this up in the long term, and the only way to do that is to keep Chinese and Iranian imports of shells and drones up, have Trump elected to stop the US from tipping back the balance, and/or get enough people elected in the EU to do it there. If Russia can keep up what they’re doing, and keep their current advance up, and replicate Avdiivka all around the front, they might reach Kyiv by summer 2026, Lviv by the end of 2027, maybe.
This is far from over, unfortunately, and a lot of Ukrainians and Russians will die until it ends either way. Russia has some advantage right now, but not enough to break the stalemate, as evidenced by the last 4 months.