Oh! My mistake. I thought the article was about some newly-published German study and that the English links were just references to other, related studies. This is the other study they linked ("Does iPhone night shift mitigate negative effects of smartphone use on sleep outcomes in emerging adults?"): https://doi.org/10.1016/j.sleh.2021.03.005

It's possible I'm missing something, as neither seems to be about retinal toxicity (i.e., "danger"), just eye strain and sleep duration/quality. The article you linked is about eye strain w/ "blue blocking" lenses, and the other is about the "night shift" feature of iOS.

(For reference, the blue-blocking lenses in the article you linked were ones that

>filtered blue light by front surface coating between 10% and 30% in the range of 400-500 nm. These lenses almost completely blocked transmission below 400 nm and had approximately 95% transmission between 500 and 700 nm.

so they are of the "Blokz" type that probably don't do much for computer/phone use. While displays do produce light in the 400nm-500nm range, the lenses described only attenuate it by 10%-30%.)