The issues from the first two books persist in this one, and get worse. The writing is amateurish in every respect: consistent typos and technical mistakes, abysmal pacing, no sense of narrative tension -- it's self-published and it shows. And worse than that, Lizzie is just not a particularly good or likable character. As the final book in the series, I was hoping to see some of her selfishness and immaturity smoothed out as she matures, but if anything it's even worse here because now she's a grown woman throwing temper tantrums at her husband. She's whiny, passive aggressive, and manipulative, and it's awful to read about.
And the story thread around the birth of her first child is deeply upsetting; she's suffering from what sounds for all the world like mild-to-moderate post-partum depression, and all the people she turns to for help tell her some variation on "it's not a big deal" or "just cheer up and get over it". Likewise with her reluctance to have a second baby; she had a bad experience the first time and is scared it'll happen again, and everyone around her says basically, "it wasn't that bad", "you're exaggerating", "just do it anyway and you'll be fine". And every time she has serious questions about her faith, everyone around her invariably ends up saying something along the lines of "I don't know, now stop asking questions". Because the best way to help people you love is definitely to invalidate their feelings and tell them they're silly for asking for help or reassurance.
So why two stars? Well, mainly for authenticity's sake. I mentioned in my review of the previous book that the author is an actual Amish person, which again is concerningly rare in this genre, so if you're looking for a glimpse of what life in an actual Amish community might look like, I'm more willing to trust this than most of the saccharine offerings pumped out by the evangelical presses. This book is also where Lizzie officially joins the church, so there are deeper and more explicit discussions of faith here than in the first two, which is obviously an important part of life in an Amish community and something I absolutely would not trust an evangelical author to handle fairly (the presentation of the Amish faith in a lot of evangelical-authored works, when included at all in any significant way, tends to be, shall we say, problematic). It's not a catechism, by any means, but it's certainly more than you'll get in most fiction.
But yeah, if you're looking for an engrossing work of fiction with an absorbing plot and engaging characters, this isn't the series you're looking for.