Are you saying that without the modifier it's impossible to make it work with move_to_min_combat_range at all? I thought maybe it would be possible to use SCaR to flip the variable instead of a modifier, but then I don't actually know how to use SCaR yet lol.
Well, without a modifier, you cannot!
To change a stat on the game you need an existing modifier. And as you said, there is no modifier that changes the move_to_min_combat_range value, for entities.
And SCaR cannot change that either.
But with SCaR, you can try alternatives. For example:
1] See if the unit is using the ability.
2] If yes, then see if the distance from target is the minimum required.
3] If not, then find the vector difference, and then find the new min range x,z coordinates and give the squad the command to move there, IF the target remains the same.
It is "relatively" easy to do for someone with SCaR knowledge (although finding the original target, and target swapping will indeed be a challenge to code properly).
I think you must ditch it for now...