Yeah, unfortunately, AST is the Chronomancer. Or Time Mage. Given that Time Magic is derived from the original 時空魔法 or "Time and Space Magic" and that's what AST uses, Time and Space magic.

Between Lightspeed, Gravity, Time Dilation, Combust, Helios, Celestial Opposition, Earthly Star, Stellar Detonation as well as the cards based on constellations, their kit utilizes what can only be described as "Time and Space Magic"

Other classic Time Magic spells have been integrated into the game as generic effects. Regen is something that WHM and AST (With Diurnal Sect) apply, Slow is applied by various skills, Stop is essentially Stun, Immobilize is essentially Bind, Disable is essentially Pacify (Though it used to be an actual AST skill that reduced a targets potency by 5-10%)