I've never had an issue with subtitles, so I prefer the German version with the English subtitles. I tried the dubbed version, and its decent, but it takes away from the dialogue in certain scenes so I ended up noticing when it was off slightly and it bothered me
And yea, a rewatch of the previous season is pretty much an essential for this show lol.
For a show with so many complexities going, they've always done a great job of tying everything together, so I'm a bit nervous as well but more so excited. Season 2 I was in the same boat about the future setting, but like you said, they handled it very well. Its almost strange how this show seems to have such little hype, it truly is an incredibly fascinating show with a plot that sucks you in. It went from a show I had no prior knowledge of to one of the few "can't miss" hidden gems for me. I've suggested it to so many people at this point and they've loved it. Cant wait for the finale.