I found several parts of this article interesting, including this:
The Purdue study found that switching from light mode to dark mode at 100% brightness saves an average of 39%-47% battery power. So turning on dark mode while your phone’s screen is that bright could allow your phone to last a lot longer than if you had stayed in light mode.
After getting the new 2021 iPad Pro 12.9, I’m finding myself using dark mode a lot more, not so much to save battery, but because the black is so black everything looks fantastic.