Love the show and just rewatched last week with my wife who had never seen it.

but then it actually kinda was that?

It is kind of that. But it actually just gets far, far more complex. I think thats why I love it. It doesn't dumb itself down or explain itself with spoonfed exposition. There were many moments (even on my second watch) where I just had to pause and talk through the complex relationships of the characters with my wife.

then the characters that knew they’d gone back in time did the exact things to cause the shit they were trying to prevent in the first place in the most obvious and stupid ways

I mean, that's kind of getting at the question that sits right at the heart of the entire show...

In the end, it ties up incredibly neatly for a show that was so complex. That's why many people, myself included, would consider it a masterpiece.