I really enjoyed this first issue, Sana has felt like a character that could carry her own series and it's great that they're finally doing that.
It's interesting that you read this story as taking place earlier in the timeline, I thought it was taking place concurrent to all the other comic series (except for Han and Chewie). The mention of a breakup is a good indication that you're probably correct, I just assumed it was talking about a breakup that hasn't happened yet.