Goofy has ALWAYS been able to revert back from G4/G5 if he doesn’t use up all its Haki/stamina
If he deactivates it himself: he’s fine and can move. See Cracker, Katakuri, Yamato combo-attack, Numbers
If he’s forced out of it: he’s out and immobile. See Doffy, Rooftop, Kaido 1v1
That’s the way it’s always been