You do realise that, once you have extracted everything for the class you’re playing, you can select an item for another class in the loyalty bonus. At the bottom-left of the dialog there’s a drop-down list, which shows all the classes, pick one that’s not your current class, and select an item for that class. Your extractions will go towards unlocking that other class’s item.
Back in March, when we had less classes and items per class, I posted this thread…
…which showed that at the 100 extractions per week cap, it would take over 20 years to unlock all the essences for all the classes. I’d frankly be amazed if you have actually acquired every single essence for every single class.