Galactus's cosmic reality manipulation gives him tools that even Ultra Instinct Goku cannot counter.
Ultra Instinct Goku is one of anime's most powerful characters, with feats approaching universal scale. But a well-fed Galactus does not fight on physical terms โ he manipulates reality, energy, and matter at a fundamental level. Goku's incredible speed and power mean nothing if Galactus can simply alter the fabric of space around him.
Goku's advantage is his combat speed and ability to scale beyond any opponent. Ultra Instinct gives him autonomous dodge that reacts faster than thought. But Galactus's attacks are not conventional โ cosmic energy blasts, molecular transmutation, and reality warping do not follow the physics that Ultra Instinct is designed to counter.
A starving Galactus could lose this fight. Goku at his peak is genuinely universal in power, and a weakened Galactus has been hurt by far less. But a well-fed Galactus is a cosmic constant, and his Power Cosmic simply operates on a different axis than ki-based combat.
Galactus wields the Power Cosmic which manipulates reality at a fundamental level โ molecular transmutation, energy draining, and cosmic force fields that operate beyond physical combat. A well-fed Galactus is near omnipotent.
Ultra Instinct Goku has universal-level power feats and autonomous reaction speed that transcends thought. His ki attacks can threaten dimensions, and his Saiyan biology means he grows stronger during battle.
A well-fed Galactus wins through cosmic hax that bypass Goku's physical combat abilities. A starving Galactus could lose to UI Goku's universal-scale attacks. The outcome heavily depends on Galactus's power level.
Galactus also fights
Goku also fights