PSA: You can hide your class gauge behind your minimap.

I know they can be useful, but as a paladin, my Oath Gauge does almost nothing right now besides pulse obnoxiously in the corner of my screen, so I tried to hide it in the HUD Editor only to learn you literally can't hide it for some reason. So I got creative!!

In HUD Layout, shrink your class gauge to as small as it'll go (60%) and then move it over your minimap and save. Then click on your minimap to open it up, and it'll layer over your gauge! Boom, gone.

This might not hide quite as well depending on your class, but it hid my paladin gauge well enough at least.

Examples: 1, 2

EDIT: Y'all, I know how to hide windows in the HUD Layout. I can hide anything on my HUD by right clicking it, except for the class gauge. Right clicking on it in the layout editor just doesn't do anything.