Later seasons of Dark got really really weird and hard to follow for me..hopefully you’ll like it better..
I'm almost done with
Dark. I have a few more episodes to go. Your observation is a common one. I still suggest people watch at least the first two seasons. And if you like it and see where it is going, continue. Otherwise you are fine ending at Season 2. Plenty of enjoyment from that.
The story is incredibly intricate and well thought out. The sets are superb with alternate year settings done very well. The acting and direction is top notch. The English dub is too bright and loud, and not always the best. (Also, how does only one family member have an Irish accent?) They also missed an opportunity to properly translate a joke in season 2, which is about the only joke in the whole series. Still, if you want to understand it best, the English dub is most accessible.
Quick view tip: when you hear a "click" on scene changes, the year changed. Second tip: after about episode 7 of season 1, pull up the "Family Tree" section of wikipedia for season 1. Do not look at any other wikipedia section. Do not pull it up before episode 7, otherwise you risk spoilers. The family tree will help you make some sense and keep track of the long character list. Look only at the family tree for your season.
I've never seen
Stranger Things. It is next on my list. Comparisons have been made by others. I find comparisons to
Twin Peaks. Except,
Dark is efficiently German and tries to be pseuo-scientific, whereas
Twin Peaks was artistic with pure fantasy. There are no backward talking little men in
Dark.
Dark has almost zero humor too. There's a reason it is
Dark.
After I finish, it will be time to watch in German with the German captions. I know some German, but the slang and complex topics eventually got me. I think on a second try it will be fun since I'll have context.
Oh, BTW, if
Back To the Future uses simple math, then consider
Dark like this: season 1 - simple math, season 2 - algebra, season 3 - calculus. And yes, they do briefly reference
Back To The Future. Why not?