First thing first, I agree with previous comments, especially from ohkimch who pointed out many of the flaws within the story. I feel the same way as well.
But I am backing it up a little here. It is based on a fairy tale story: it's old, it's ancient. Thus, it reflects the thinking and values of the people at the time - which many of us here considered backward, sexist, misogynic, abusive, frankly problematic throughout. And they are learning points for us to see into, reflect and discuss in comparison with what we have going on today, to see progresses and look forward to what can be and will be.
Same thing with the literature we study at school (some might say Scarlet Letter is maddening or How To Kill a Mockingbird portrays white-savior syndromes), but we still study them because they are part of our histories and social constructs (please refer to literatures from your native lands as examples).
There has always been darkness as there has always been light (albeit more or less of the other). So we still get to see something good out of all these. Please be reminded, in the original story, the Princess was casted aside at the end. Here, the author goes further to illustrate what might happen afterward. Do I agree with all the horrible things happened by so many forces and by the protagonists themselves? Based on my present set of values: No.
But it was a relief and a sense of satisfaction for the happy ending and the thoughts and growths of the characters. To me, the author clearly thinks it through and really tries to put herself into the situation and twists and turns them so they turn out (somewhat) positive, hopeful and nice at the end - which is what most of us humans strive for in the bad/horrible circumstances - and which I really appreciate.
On a personal note, I usually avoid "smut". Often, the collection bores me with the mindless physicality and repetition of lust without much thoughts into the characters or their surrounding, be it shoujo or josei or LGBTQ+ stories.
However, I must commend the execution here. It is arousing (well, smut is supposed to be so). Yet it leaves me with after thoughts of the conducts and the feelings of the characters. That is why I subject this as "well-done smut". It's not there just for the pleasure. It's short the story, yet it makes you think beyond.
Again, the previous comments and opinions are all valid. At the same time, I encourage anyone to just go for the story, then form your own thoughts and feelings on it. Be open-minded if you can. Recognise what you like or dislike. Props or condemn the author afterward. Most importantly, learn the lessons that befit you while also take into account the differences of others.
Enjoy!