I really enjoyed Nora and Javier's story! I got to beta read this one, and since I knew it was based on Daddy-Long-Legs by Jean Webster, I read that first which meant I noticed all of the references, comparisons, etc. it isn't necessary to read that or the other three in this series to read this one, but it does have a extra layer of enjoyment knowing the background. 

Nora is alone in life, only really had her mom who then passed away when she was 19. Now at 26, she's about to leave the charity that gave her scholarships and room and board for undergrad and her Master's. She's given an opportunity to join an entrepreneur incubator by a mystery benefactor who also supports her old home. She doesn't know who he is but is required to write monthly progress emails that he may not even read, and she ends up using them more like a one sided pen pal or diary. On the other end is Javier, billionaire philanthropist trying to spend as much of his family's money as he can by supporting various causes and giving people chances they wouldn't have received because they weren't born into money like he was. He's also Latino on one side of his family and when he learns from Nora's emails that she feels so out of place in the program because of her own economic and racial statuses, he decides to be her friend. But not as her mysterious Mr.B, but as Javier (luckily, his niece who is basically the same age as him is also in the program so he engineers a way for them to meet). They grow closer, and though both of them assumed they'd never be interested in romance or long term relationships, they start to crave it with each other. One problem: she doesn't know he's both men. This retelling does what the original did not, and gives us the emotions and the reckoning that we'd expect once she does find out. I liked what the author did with their story and the pacing of it afterwards while they tried to figure things out. 
As usual with this series, I laughed (the banter really is excellent and their senses of humor in this one were right up my alley), I teared up multiple times and did actually cry once because I could feel the emotions. Again, the fat and queer rep were so great. The way Leonor writes men who love their lucious ladies makes me so happy, the way they are attracted to them and year for them is not something plus sized folks are taught to want for themselves so I think it's powerful. Also, Nora's queer identity is mentioned super casually in her internal monologue the first time and I absolutely love that. Yes, she does tell him at one point and inject humor into things, but I think there needs to be more quiet queer rep in books, the same way staying that someone is a redhead is just part of them. This one is very much a slow burn but once it burns, it burns! As the last book in this series, I expected it to wrap things up well and I think the second epilogue ended the series in a satisfying way. I appreciated that there was the first epilogue to wrap up this story specifically, and then the second to continue it and show us a bit of the future for the entire friend group. It didn't feel rushed or forced, or like I didn't get enough. Would I have accepted more? Of course! But there are some final books in some series where I end up disappointed by the wrap up, and that wasn't the case here. Especially since there may be more books set in Laguna Island where Max and Eva live, so I'm sure we'll see some of all of these folks again someday. 
Overall, I'm glad I got to read this one in its various versions (beta, arc, and completed), and though I don't believe there can be any ethical billionaire in reality, the fictional ones in this series do it in a way that didn't bug me. 

Re-read update: I read the arc version this time and it was so fun to see moments in the book that changed because of my comments/suggestions! I'm certain there were also other changes that I just didn't notice because of how quickly my brain fog releases details I don't specifically focus on, but there were definitely some moments I thought to myself 'is this new? Feels like such and such was fleshed out more maybe'. The story is tighter and even stronger, and even thought I just read if a few weeks ago, I still really enjoyed Nora and Javier's love story! Also, moving the second epilogue to a free short story it you subscribe to the newsletter was an interesting choice. I can see why she made it but it does make the book feel a little incomplete--but probably only to those of us know read it as part of the ending originally; readers who read it for the first time probably won't notice it and will be fine with the ending.