The Minks have been waiting on the Dawn for centuries. The Kozuki have been waiting on the Dawn. According to Yamato, Momonosuke will lead the world through the Dawn.
The Sun God the Shandians made sacrifices to, the sun the Elbaf giants pay tribute to with 12 days of fasting, the Dawn the Minks are waiting for, and the former Fishmen slaves creating the Sun Pirates. Zero chance this is all a coincidence and Oda is seeking to tie the mythologies of the One Piece world together. Is it Joy Boy related? Well, there is one damning piece of evidence with a sun right next to a giant upside down strawhat, all in the ancient lunar Shandian civilization discovered by the one true God Enel.
There are also a lot of sun references with Luffy. In Dressrosa and Wano he wore things related to the sun.
Also Luffy’s straw hat could be related to the sun.
At Dawn/Sunset, the light rays coming from the sun travel through a thicker and longer atmosphere (the horizon to the beholder’s eyes) which in turn cuts out the shorter wavelenghts of light (such as blue, green, etc…) while the one that is able to pass the most is the red wavelenght, hence a red-ribbon-like phenomena.
And finally, this: