I think there are a few key paragraphs in this article that provide important context to the post title:

1. “Russia’s military has displayed “professional qualities” by preventing Ukrainian forces from “advancing quickly”.”

So they’re advancing, just not quickly enough for someone’s timeline?

2. “The Institute for the Study of War says Ukrainian forces appear to have broken through “certain pre-prepared Russian defensive positions”.”

So the Ukrainians are advancing, even through readied russian defenses.

3. “So far there’s little evidence that Western supplied tanks and armoured vehicles have been able to tip the balance decisively in Ukraine’s favour.”

So there’s no context for what they mean by decisively, But since we know that the Ukrainians are advancing because of these tanks and even breaking through pre-prepared Russian defenses, the armored vehicles are clearly tipping the battle in Ukraine’s favor.

Oops… the fact that the Ukrainians are attacking defenses that have been built in-depth tells me that the Russians had a pretty good idea where the Ukrainians were going to attack - this does not bode well for Ukraine.