Hi, I'm the author. I read over 20 studies before writing this post and stand by my conclusion: there is not conclusive evidence blue spectrum light specifically is worse than other illumination.
I only linked to the most interesting outliers that could not reproduce the most cited study's findings. I also linked to the most rigorous study (3 groups: using Night Shift, not using Night Shift, not using phone at all in a natural setting instead of lab) with the largest sample size (167 people) and duration (7 consecutive nights) that found no observable benefit from using Night Shift, only not using a phone before bed.
I only linked to the most interesting outliers that could not reproduce the most cited study's findings. I also linked to the most rigorous study (3 groups: using Night Shift, not using Night Shift, not using phone at all in a natural setting instead of lab) with the largest sample size (167 people) and duration (7 consecutive nights) that found no observable benefit from using Night Shift, only not using a phone before bed.
Here's another rigorous study in a lab setting with similar conclusions: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6561503/