How do you replicate a uobject?

Okay, you can use UObjects not AActors.
In your owner class implementation of ReplicateSubobjects must be looks like this:

bool AMyGameMode::ReplicateSubobjects(class UActorChannel *Channel, class FOutBunch *Bunch, FReplicationFlags *RepFlags)
{
    bool WroteSomething = Super::ReplicateSubobjects(Channel, Bunch, RepFlags);
	
	
	for (auto& item : Items)
		WroteSomething |= Channel->ReplicateSubobject(item, *Bunch, *RepFlags);
 
    return WroteSomething;
}

Replicate every item individually