Ah memories, I had a custom msstyle back then and dabbled with WIndowBlinds too. Those were the times.
It's like on Android too, for years many of us ran rootless themes or even rooted theme engines but now that we have system wide dark mode, this is a thing of the past. It's a shame that a desktop OS that has been around far longer simply has not caught up. What's bizarre is that MS had a proper dark theme in Windows Mobile when the Lumia phones were a thing yet..... They neglected to put effort into desktop Windows :/