Retreating fleets disperse and then regroup again once safe.
Not necessarily. “Disperse then regroup” is a tactic that was used – and only as a desparate last resort – by convoys of merchant vessels under heavy enemy attack. I’m not aware of warship fleets using this technique extensively in WWII; some naval tacticians like Wayne Hughes have argued that warships are actually in a much better position when they’re concentrated than when they’re dispersed.
The Japanese fleet at Midway didn’t disperse as a result of its defeat because it was already dispersed when the operation started. In his book Miracle at Midway, Gordon Prange faulted Yamamoto for his dispositions in the Midway operation: the Japanese fleet was broken up into several widely-separted forces, none of which was close enough to the other to provide any meaningful assistance to each other. This dispersion wasted the enormous numerical superiority that the Japanese had over the Americans. In fairness, the Japanese Navy as a whole (and not just Yamamoto) had a fondness for elaborate operations involving multiple fleets; their operation at Leyte Gulf in 1944 was another example.