1, it seems that Qu Yuan wrote 28 "suicide notes" when he died, which has no basis in history.
2. Biography of Qu Yuan in Historical Records records: "This is a' Huai Sha' Fu. . . . . So he fell in love with this stone and threw himself into Miluo to die. Some people confuse "Huai Sha" with "Shi Huai" and think that "Huai Sha" means drowning suicide. Academic circles have long denied this wrong view.
Huai Sha is just one of the Nine Songs. "Sand" refers to Changsha.
Qu Yuan's handed down works far exceed the 28 sentences you said. In addition, quatrains, as a form of expression of poetry, mainly prevailed in the Tang Dynasty, which was different from regular poetry, ancient prose and Yuefu.
Many years ago, Hong Kong made the film Qu Yuan (starring Bao Fang), which told the story of Qu Yuan's life and contained many fictional elements. Literary and artistic works are not historical facts after all.