[DeepL Translation - needs review] Volume 1 Introduction: There is no such thing as a sister who doesn't like her sister. All older sisters in this world love their younger sisters. I, "Shima Sakura," have a younger sister. A very, very cute little sister.
(Translator: DeepL)
There's even more of the mom being creepy :( But otherwise it's enjoyable like the last volume, except more time with the side characters - which I found the love polygon aspect amusing and enjoyable. I feel bad for Yuu tho.
The next volume is the weakest of the 3. So if you're on the fence at this point, you can probably just stop after this volume