Grimly Gripping Rabbithole I'm not the first person to point out that this innovative and fascinating series can't and shouldn't be blithely, erroneously and fatuously pigeonholed as a German "Stranger Things". The only thing it has in common with that series is that it is partially set in the 1980s. And there end any and all similarities.
If you need a point of reference for "Dark", look no further than "Primer". Themes of multiple, intertwined timelines, cause and effect, collide with familial chicanery, secrets shared and buried enmities. It's basically a Greek tragedy with time travel. A darker "Back To the Future" if you like. And well worth investing in the ten episodes. I would advise that you turn subtitles on and the original actors, much more satisfying.