This is a huge life improvement: https://darkreader.org/
You can get this for CHrome/Firefox. It does break some sites, but you can turn it on/off. It also lags sometimes. But overall it’s worth it. I get migranes with the white backgrounds.
I got one request for a darker background for this site. I haven’t found any good DARK THEME for WordPress. If you know of a good one, let me know. I had that other dark gray one that kinda looked like #*#*#.