Force Add Rotation on Rotation-Locked actor?

Assuming you’re using an AStaticMeshActor. If not, do GetBodyInstance() on your component of choice. Regardless, not sure if this will work, but give it a try anyways:

if (FBodyInstance* BodyInstance = GetStaticMeshComponent()->GetBodyInstance())
{
    if (FPhysicsActorHandle ActorHandle = BodyInstance->ActorHandle)
    {
        if (Chaos::FGeometryParticleHandle* ParticleHandle = ActorHandle->GetHandle_LowLevel())
        {
            BodyInstance->bLockRotation = false;
            ParticleHandle->SetR(Rotation);
            BodyInstance->bLockRotation = true;
        }
    }
}

Let me know.