Choose a spell of 3rd level or lower from any spell list with a casting time of 1 action. Zenith's Adaptive Arcana takes effect as though it were that spell, cast with a spell slot of 2 levels lower than the slot used to cast Zenith's Adaptive Arcana.

At Higher Levels. When you cast this spell with a slot of 6th level or higher, you may choose a spell of 2 levels lower than the slot used, rather than just 3rd level.