Shift + Scroll to scroll through single columns in your inventory on your hotbar.
Alt + Scroll to scroll through all columns in your inventory on your hotbar.
Ctrl + Scroll to scroll horizontally on your hotbar.
Keybindings can be changed via Mod Menu. Mod Menu is highly recommended.
Rubik's Hotbar is still very much a work in progress and there are probably still many issues. Please create an issue for anything you find, even small things.
Created at the suggestion of Mr_Darn and named by Corvo on the fabric discord.