It's not the blue but brightness and stimulating content:
https://www.theguardian.com/lifeands...p-you-sleeping
There have been many studies debunking the blue light claim. This is not new news.
Also "dark mode" is inferior readability and was invented on phones for OLED power saving (up to 80%). No power saving on LCD. It's often better to turn the brightness down and use "white" background, but only use Auto outdoors and compare screen with paper illuminated by ambient light to set brightness. Many people have brightness too high indoors (or front light too high on mono eink).
Also reflections off a screen give a headache and make it harder to sleep as the eyes unconsciously change focus distance and tire the muscles.