I finished season 2 of Dark just today (binged it all in the last week or so) and i liked it.
I don't have a problem with the nihilism you mention, the show is almost completely devoid of any humor, but that shouldn't be a prerequisite i think (or Bergman would be a hack).
Regardless, if you like time travel stories, it's probably one of the best i've seen on the screen, this side of Primer (and significantly less complicated than Primer, lol).
It deals with all the usual plot points you find in all of them, such as time loops and paradox and so on and so forth, but puts them together with enough verosimiltude and breakneck pace to make it fun.
I wasn't really sold on episode 1 so i'd suggest to at least give it 3 or 4 episodes, to let the 50 characters set in your head a bit.
I honestly cemented who was who in which timeline, into season 2, so i guess it's normal to run mental connect-the-dots at first.
Casting director on the show should get a medal though, the way they chose various actors to represent the same character is really well done, as far as likenesses go, almost uncanny at times (i could recognize who they were even before the name drop, despite being a different actor).
Before watching i had seen people comparing it to Twin Peaks, and to be honest, aside from the general theme of parallel timelines, and a small town where everyone has a history/skeleton in the closet with one another, there isn't much else they share.
But it's a really gripping show, and the characters grow on you, even though in season 2 they sort of focus more on a couple of central ones, for better or worse, as the plot grows in scale.
Now that i think about it, in terms of tone, the show reminded me a lot of Les Revenants, only Dark is much better, as i hated that show.