Yuliia Svyrydenko, prime minister of Ukraine, gives an interview in her office in Kyiv, Ukraine, on Thursday, Sept. 18, 2025. President Volodymyr Zelensky said Svyrydenko would step down amid a broader shake-up in Ukraine’s senior leadership. (Brendan Hoffman/The New York Times) By ANDREW E. KRAMER President Volodymyr Zelenskyy announced on Sunday a shake-up of his top leadership, including the dismissal of the prime minister, in a personnel overhaul that comes as momentum in the war has…