The books were:

The Comet Seekers by Helen Sedgwick — had never heard of this and would have never picked it up because of the low Goodreads rating, but I loved it, 5 stars.

Greenwood by Michael Christie — had never heard of this, it hit a bunch of the things I said I like in books (non-chronological structure, sci fi/historical fiction genre mix, ensemble cast, focus on natural history/ecology), but I didn't love it because of the pacing, 3 stars

The History of Bees by Maja Lunde — had never heard of this, loved it, 5 stars

Ship Fever: Stories by Andrea Barrett — had never heard of this, loved it, 5 stars

The Sparrow by Mary Doria Russell — already had this one my TBR and seeing the recommendation bumped it up in line, I loved it, 5 stars

The Archive of Alternate Endings by Lindsey Drager — had never heard of this, hit a bunch of things I like (folklore, sibling relationships, many timelines) but it was a bit too experimental for me, 3 stars.

>my problem is splitting the good books with themes I like from the bad books with themes I like!

I get that! So far, I've had good luck in the sense that I haven't tried any books that I thought were bad or objectively poorly written, just things that weren't perfectly to my taste. In the preferences survey, you get to answer some questions about what you think makes a good book in terms of writing style and characters and plot, so I think that helps. It'll be interesting to me as I keep reading recommendations to see if I start encountering books that I think are just bad or whether the algorithm really can tell what "good for me" means!

*I realized this might be important to know — I tend to rate about 10 books a year 5 stars, so this was an impressive showing in my opinion. I don't give out 5 star ratings willy nilly.