Alternating or random brightness

Hi All!

I've got two lights connected via Home assistant to Node-Red. They are dimmable ikea lights and are inside a christmas star. I want the lights to change brightness subtile, alternating, to mimic real star light. They do not have to alternate simultanious, they can work independent from each other to make it more natural.
Any idea how i can make this work? Any help to point me in the correct direction is appreciated.
Thanks
Mike