Definitely a great question. I would suggest they are boiling the frog. This is how, after all, NATO go to Russia’s borders in the first place: At every step people complain, then accept the new reality. Then there is another step. Its kinda how nuclear superpowers operate. China seems doing the same economically. Their overarching goal is for the US to accept multipolarity.

They also don’t want to conquer The Ukraine, they want to denazify and demilitarize. That is actually a political, not a military goal. It involves Zelensky being perceived as the ultimate evil in the current situation. If Russia just kills him and bombs everything, then Russia is the ultimate bad guy.

Finally, we can’t rule out Zelensky having a secret weapon. He was talking big like this also befure the strategic drone attack on nuclear bombers (‘spiderweb’). And again before Kursk. Quite probably there is something else strategic currently in the pipeline, yet to play out that is buoying him up.

- Shyaku