I turn off all sorts of animations, movements, and transparencies in iOS and macOS. For the menubar, it goes to my desired theme[1] irrespective of the wallpaper when I set display to “Reduce Transparency”.

  System Preferences > Accessibility > Display ~ Reduce Transparency

1. Dark for Dock, Menu, etc but all others Light.

a. Set theme to Light, then run

b. `defaults write -g NSRequiresAquaSystemAppearance -bool Yes`

c. Logout and Choose “Dark Mode".