A story can be 'kinda funny' when there are unexpected elements. For example, if someone is expecting a normal day at work but then their boss shows up dressed as a clown. The sudden deviation from the norm makes it funny.
Humor often comes from the absurdity in a story. If things happen in a way that defies normal expectations, like a cat acting like a dog, it can be 'kinda funny'. Also, self - deprecating humor in a story where someone makes fun of themselves in a light - hearted way can also contribute to it being 'kinda funny'.
I'm not sure specifically what the'sama sama letter day story' is about as it's not a widely known common story. It could be a very personal or a story from a specific local or cultural context.
I don't think it's common. Most people would use more straightforward phrases like 'lack of new stories' or 'no new types of stories'. This phrase 'no new kinda story' has a bit of an informal and almost poetic feel to it that isn't typical in everyday language.
The Kaguya-sama manga is indeed finished. It ended after a successful run, leaving fans with memories of an engaging and enjoyable story. The final chapters tied up loose ends and delivered a conclusive ending.