Is your feature request related to a problem? Please describe.

I want to hide the text until the last 10 seconds of the cooldown, but there's no way to do that. There's a current option "Maximum Cooldown Duration" but that's slightly different - it only shows timers if the total duration of the cooldown is less than the value. I want something that shows the timer when the remaining duration is less than a value.

The closest you can get currently:
Create a new theme, call it auras or whatever. Set the Auras rule to use it (and click the enable checkbox)

Set every color and opacity color, except for soon to expire to transparent

That will cause the timer to show up when under 5s or less.