I beg the female protagonist to be adopted by the male protagonist. The male protagonist has always loved the female protagonist. For comics like "Flowers and Demons", the male protagonist should be a

Flowers and Devils....

The ones most similar to it should be Ken Saito's The Name of the Flower and Hako's A Love Story.

It is also a nurturing series, and the male protagonist is also a little gray, a little awkward and likes his silly child.

Speaking of the cultivation system...

The Tale of Genji (Yamato and the Chronicles of Japan) cannot but be mentioned...