If youre looking for a couple of morally gray cinnamon rolls that are blindly obsessed with each other, you have found the right book.
There really isnt a plot other than them becoming a couple, and thats chill - i needed a cute little palate cleanser.

It doesnt actually seem like these books NEED to be read in order due to any overarching plot- this is my first book ive read of the series and there wasn't some over arching plot to consider. Like yes you get some info on other couples and they might discuss big moments for others but that's  not usually a deal breaker for me when reading this type of book where its mostly about watching characters be all up in their feels and trying to figure out how to vibe with each other.

But on the other hand, there are other couple POVs in the books it seems so maybe you read in order so that you get the full scope of the characters? Regardless, do whatever you want lol