Indeed, both components and other subobjects of the actor eventually get destroyed by being detected as unreachable by GC:
> UnrealEditor-Engine.dll!UActorComponent::DestroyComponent(bool bPromoteChildren) Line 1561 C++ UnrealEditor-Engine.dll!USceneComponent::DestroyComponent(bool bPromoteChildren) Line 1188 C++ UnrealEditor-Engine.dll!UCameraComponent::OnComponentDestroyed(bool bDestroyingHierarchy) Line 143 C++ UnrealEditor-Engine.dll!UActorComponent::BeginDestroy() Line 826 C++ UnrealEditor-CoreUObject.dll!UObject::ConditionalBeginDestroy() Line 1220 C++ UnrealEditor-CoreUObject.dll!UnhashUnreachableObjects(bool bUseTimeLimit, double TimeLimit) Line 5928 C++ UnrealEditor-CoreUObject.dll!UE::GC::PostCollectGarbageImpl<1>(EObjectFlags KeepFlags) Line 5547 C++ UnrealEditor-CoreUObject.dll!UE::GC::FReachabilityAnalysisState::PerformReachabilityAnalysisAndConditionallyPurgeGarbage(bool bReachabilityUsingTimeLimit) Line 5746 C++Glad to provide this info!