There is no doubt that the Ukrainian armed forces are on the defensive across the board. The president will have to come up with more than just this one personality.
Anyone who replaces a general in the middle of a war must already have defeat in mind. Why else would Ukrainian President Volodymyr Zelensky fire his top officer at a time when hardly anyone would bet on victory in the fight against the Russian aggressor? After the failed offensive in the summer of 2023, Ukraine has clearly gone on the defensive: militarily and politically. So Zelensky needs success, no matter what kind.