“Armstrong like Mearsheimer has been predicting Ukrainian defeat for over two years now.”
Let’s see. The Ruskies have taken eastern Ukraine and town after town is falling into their hands. Is there any other data you can provide that shows the opposite?
How are things going in Terny and other places? 300+ armored vehicles destroyed after a few months of fighting & the Ukes retook 1.5Km after the Russians exhausted their reserves. That's actually settling into a persistent pattern: the Ukes defend and fall back slightly and then hammer the Russians more until the Russians run out of local reserves and then counter attack.
The Russians are squandering huge amounts of infantry and making very little gain even when the Ukes are outnumbered 7:1. Putin will run out of infantry before Ukraine does if this keeps up. The Ukrainians are now getting a full stock of artillery rounds and have really improved their drone use. This is isn't going to get any better for the Russians.