The Ukranians can fire back? Such as at Belgorod? Besides, even rocket artillery range is only about 30km. Kyiv is now out of range of everything except airstrikes, and Russian air power is of limited effectiveness as they never achieved air superiority.
It is quite possible the Ukranians will retake everything taken in the recent offensive. The question is then whether they will also attempt to retake Donetsk, Luhansk, and Crimea.
Why stop at reclaiming former Ukrainian areas defined post USSR collapse?
It would be beneficial to the world to see a Novo Ukraine, a wealthy country committed to peace and modeled with a federalist system, taught by the mobocratic failures of the last 30 years, stretching from eastern Europe to Siberia.
It is quite possible the Ukranians will retake everything taken in the recent offensive. The question is then whether they will also attempt to retake Donetsk, Luhansk, and Crimea.
It probably will be a long war if they do.