you could use UI layouts to emulate it.
Just attach a HitTestSphere model as an attachment.
You can use a Unit Order Queue validator to determine if a unit uses an ability on another unit. Big issue is linking the two objects if there is more than one pair. Someone made a trigger library for waygates which you might find useful.
You need an automatic Morph ability validated by Enumerate Area validators.
Here is a demo map showing the concept: https://www.sc2mapster.com/projects/the-assets-of-evil/files/2499784
Check the filters for the spash of the Damage effect.
Ok then other causes could be the Turret type actor is not being created or you have not set something under the Combat: Weapons fields of the unit.
Ok the weapon arc must be 0 to give it a reason to use the turret.
Does it shoot at the target? Weapon got an arc of <360?
Well there is a template map for custom commanders so there is nothing stopping you from implementing your idea.
That looks like the loading bar from the left 2 die map of blizzard.