Next healer class released should be

[BasicBlake]

It doesn't have to be inventory based. In FFX-2 the (Al)chemist class could use potions regardless, even if you didn't have them in your inventory. Said skills were called "Stash" skills, and were describe as such by the game's Help description, "Use a hidden item. Takes time, but no item are expended."

https://ffxiclopedia.fandom.com/wiki/Trust:_Monberaux

Another version of a Chemist healer not using inventory to heal