How to properly null an 'Object' reference so it gets garbage collected? (Preferably in Blueprints)?

I have an ‘Object’ derived class. I’m constructing an object from this class at runtime using ‘Construct Object from Class’ and storing it in a variable. The ‘Outer Object’ is an actor BP.
Later when I need to destroy the object, I’m setting the variable to null. But it seems that’s not enough to make this object get garbage collected.
The Actor BP that is the ‘Outer’ of the object is not letting it get Garbage Collected. The actor BP has to be destroyed and then the object gets garbage collected. But I don’t want to destroy the Actor.
Is there a way to set the ‘Outer’ of an object to null? Or some other way to garbage collect it?
Preferably in Blueprints?