Usage

The bathtub works mostly like a cauldron, it can be filled with a water bucket or bottle, or if there's a water source one block under the floor it will grab that water instead when clicked on. It can be used to remove dye off of armor and shulker boxes, it can extinguish fire and it outputs a comparator signal as well. During the day you can also sit in it, and at night sleep in it.

Crafting

The bathtub can be crafted with quartz, a couple stone buttons and a bucket.