I'm pessimistic about Ukraine's chances of liberating much of Russian-held territory. Up till now the Ukrainians have tied up Russian troops in a deep defensive belt in the east while sending tank hunting teams to destroy Russian armor and generally demoralize the Russians. The Ukies turned out to be pretty good at this. But it now seems that the Russians are holding most of the territory south and east of the Dneiper River and are going over to the strategic defensive. So now the shoe is on the other foot. UA has to attack prepared defensive positions. And they already appear to be on point of mutiny.
There was a good interview in Die Welt yesterday with Ukrainian troops getting some R&R about 20km back from Severodonetsk. Grimly determined is how I would judge their comments, including one guy whose unit went from 700 men to 120. The UA appears to be waiting for the Russians to exhaust themselves. They prepare deep defensive works a couple of kilometers behind the front, fight in the existing lines and then fall back. With the whole battlefield inside both sides' artillery, it's murderous. But the Russians must be getting hammered. There are also at least two brigades of armor the Ukrainians got from Poland being held in reserve. So they are giving ground very slowly and waiting for a counteroffensive. Whether they can succeed or not is unclear.