You can’t trigger OnComponentBeginOverlap event OnBeginPlay even if the Object spawns inside Collision.
The solution (a workaround) to this is to trigger desired behaviour from OnComponentBeginOverlap event inside OnBeginPlay. You basically need to call your nodes from OnComponentBeginOverlap event inside OnBeginPlay event to create desired behaviour. Since you have full control over initial setup of all your objects (OnBeginPlay) you can just use it to your advantage and directly call nodes you need.