I'd say it's likely a case of misinterpretation. Maybe there are similarities that you overlooked or differences that you focused on too much, leading to the conclusion that it's not the intended manga.
Sister Lover was a Japanese manga about the love story between the protagonist and his half-sister. The ending of the manga had not been decided yet because the storyline had not yet ended. Some readers and the media speculated that the manga might usher in a happy ending where the protagonist and his half-sister could find their own happiness. However, these speculations were just speculations. The details of the ending of the manga would only be known after the work was completed.
The 52nd chapter of the manga "Confession to a Beautiful Master at the Beginning" was about his master being poisoned by the green lotus. The specific plot and plot could only be understood by reading the manga.
Yes, there is a manga for Takt Op Destiny. It offers another way to immerse oneself in the world and adventures of the series. The art style might differ from what you expect, but it still brings the story to life.