The funniest part of that whole thing was when someone said "I trusted you, but you use light mode on your terminal" and then he replied that people stop by his desk daily just to make fun of him for it.
Of your criteria is battery life, dark mode is most likely better
If your criteria is eye damage/strain, then IIRC the research is divided on this topic
black on white is easier to read than white on black full stop, no astigmatism necessary.
https://esa.org/communication-engagement/2018/08/03/resource...
ambient lightning is highly recommended to not strain your vision.
yes it's all preference, vision is subjective, but being surprised that dark mode isn't best is in this context... weird.
My eyes are getting old. Black text on white background is more legible/clear.