Based on my reading of different sources, this is what I see happening. ISW says Russia will attack with everything they have, especially armor, until the mud sets in. Their goal is to cross open terrain and get right up next to many settlements. Then it will be muddy and they'll stop using armor and switch to their favorite consumable, meat. So there will be a winter of horrifying meat assaults all along the front, with little armor to back them up. Probably any armored vehicle that can move is about gone by now, so Russia will spend the next 6 months building up a new armored force while attacking over muddy ground with poorly supported infantry. Then in the summer they'll do the same thing using armor over open terrain, and try and repeat 2024 in 2025 by ending with meat assaults. However, they will then be about out of Soviet vehicles, so their method stops working summer-fall-2026. They'll still have refurb and new vehicles, just in insufficient numbers. They have until then to think of something else, or they will no longer be able to seize territory or defend except with trenches. Also their economy will be doing quite poorly by then.
There will be a continued gradual decline in the quantity and quality of armor, and it will take more Russians to make up for it. 2% of all Russian men are apparently already casualties. A year from now it may be over 3%, and rising at a growing rate. The rate of Russian casualties per day has already roughly doubled from 2023 based on my memory. In summary, I see things going as they have been through fall 2026, unless something happens to change it. Variables are mostly from outside countries such as the US and unlikely China, or else events in Russia. European countries are individually too small to be variables unless they do something drastic. I don't see Ukrainians as variables, if you are going to be killed painfully by Russians anyway, you may as well take an average of 6 of them with you.