I would also like to say that I need this feature. Evernote has slowly become my least-favorite application because all of my other apps offer this.
I just cancelled my premium subscription because of the lack of dark mode on Windows.
For now, I will just have to use the web app because my browser can at least fake a dark mode. This is a horrible work-around solution.
I sympathize with the developers. I know it is not as easy as many people probably think.. but I am not happy about this lack of such a basic feature for years after it is available on other platforms.