Nord Light was also pretty good when I tried it. I waffle back and forth between light and dark themes now and then and there's always a few good options that brighten the space without flashbanging you.
Now I'm wondering if historically people started writing on blackboards first or in paper. Etching into wood/stone doesn't count since it lacks contrast.
If you look at the Lascaux cave paintings, there's great potential for a soft earthy color theme imho. Black and red on off-white, similar colors as medieval vellum with black ink and vermillion red/orange.
Well, you're half right. White was popularized by early home computers looking to reproduce paper digitally. Apple, Amiga, and Atari all did this and it stuck around a very long time. In fact, many environments are still in transition away from white.
Notable exceptions included professional audio and video environments who got into the dark themes early because they didn't want glare from their workstations affecting what they saw when editing in their dark studios.