If a volume equivalent to 1,000 times that of Jupiter's mass in water were rapidly injected into the

Injecting a volume equivalent to 1,000 times that of Jupiter's mass in water into the Sun's core wouldn't extinguish it. The Sun is immensely massive, with its core under extreme pressure and temperature, undergoing nuclear fusion reactions. While such an injection would disrupt the Sun's equilibrium temporarily, it wouldn't extinguish it. The Sun would eventually return to its normal state, continuing its fusion processes.