Greentext

Thank you for replying, because it reminded me to look for actual studies today :) Edit: If you want a TL:DR, I found this article which describes the study I found below in less technical terms. Basically it may not just be blue light that's bad (supporting what you said), although using blue-light blockers and night modes is still a good idea.

I found this 2023 study that (via a lot of technical detail) basically says it doesn't matter if the light is blue or yellow. The authors say theirs was a smaller study limited to 16 participants and shorter exposure times by budget constraints, but it supports what you said. If you scroll down to the last paragraph they say exposure to short-wavelength light (blue-to-yellow) should be reduced in the evening, and recommend phones, computers etc. have various kinds of night modes and that they be used.

So the summary seems to be that there's a study that says blue light IS hard on sleep, but it's not just blue light - it's all light with more energy than red/orange light (i.e. the light you'd get naturally at sunset). It's just one study and a small one, but that may be what you read and it's a good starting point for further research.