I tried this but it didn’t quite work for me. (I am on WA 3.1.9 for reference.) However, you DID give me some great ideas! Let me share what I did:
On Display tab:
Cooldown Settings:
Show Cooldown, Cooldown Swipe, Hide Cooldown Text, Inverse
Glow 1: Show Glow unchecked but your preferred glow style selected
On Trigger tab:
Required for Activation: Any Triggers
Trigger 1: Status>Cooldown Progress (Spell)>Spell checked, your spell name
Remaining Time: <= your preferred counter time (for me I set 15 sec)
Show>On Cooldown is selected by default and cannot be changed
Click Add Trigger and add Trigger 2: Status>Action Usable>Your spell, leave all else unchecked
On Conditions tab: If All Of>Trigger 2>Active = True, then Glow>Visibility> checkmark
Add condition> And Glow>Type>your preferred glow type
What this does is it shows me the icon with the cooldown timer when it’s almost off cooldown, and then shows me the glow with the full icon when it is off CD. It then disappears when the spell has been used, only appearing again when the spell meets the timer requirements.
Load tab: In Combat, Not in vehicle (tweak to your preference)
In my example, Avenging Wrath shows immediately on entering combat with the glow. I use Avenging Wrath and the icon disappears. The icon reappears with the cooldown timer showing 15 seconds prior to it coming off CD, and then it shows fully displayed with glow once off CD.
Hope that helps!