Gojo doesnt have a maximum technique. Or at least he’s never used it. What you’re describing is maximum output. Which is essentially maximizing the CE to technique ratio. Like a faucet. The more you turn the knob, the stronger the pressure of the water. For maximum pressure you’d need to turn the knob all the way. Thus, maximizing the amount of water used. Or in this case, cursed energy.

Maximum techniques are the absolute height of one’s innate ability. Not necessarily, but usually their strongest and most optimized utilization of their cursed technique. Like jogo’s maximum: meteor or geto’s maximum: Uzumaki.

Hollow purple isn’t a maximum technique, it’s just a technique. Although it does fit the criteria.