Something I've never seen done quite right (at least not in 1.12), and which seems like it'd fit the mod.

A block, perhaps some sort of cauldron or vat, which combines fluids with items to create item and/or fluid outputs, and which is able to take a configurable amount of time to do so (like "stewing" an item or soaking it.) A heat source component would also be really good (different recipes available if the stewing pot is over fire/lava.)

Or possibly separate blocks - a barrel for fluid+items crafting with no heat, a cauldron/pot for fluid+items crafting with heat.

Types of recipes I would see this covering:

item(s) + fluid = item (consuming fluid and item(s) per recipe execution) - essentially "soaking"
item(s) + fluid = fluid (consuming item(s) and transforming fluid per recipe execution) - essentially "dissolving"
item(s) + fluid = different item(s) and fluid