Is there any desktop OS with a dark theme out of the box?

[RoGeorge]

For a desktop with one or more big monitors, a dark theme is a must have, this is not a matter of preferences.
Though I don't remember any Linux distro with a dark theme by default.

Most of them allow customization, but at least for KDE Plasma, this never really works. For example, if I set a dark global theme, then I have to make manual changes in Kate (the default text editor in KDE), or in LibreOffice Calc, or else only the frame of the window respects the global theme, if at all.

Sure, I could manually change the background, but then I have to adjust the text coloring to remain clearly visible on the new backround, then the selected/not selected text visibility, and so on. Then again for another coloring in another language. Then it's the Qt4/Qt5/Gtk2/Gtk3 and so on, all defaulting to light themes.

Setting the entire OS to use only the dark theme is tedious mess.

Is there other easier way to set all programs to dark mode?
Is there any OS with all the defaults to a dark mode?

[Fred27]

this is not a matter of preferences.

Of course it is. Not everyone wants exactly the same as you. 

[DiTBho]

out of the box -> try Pop!_OS (by System76): it's Linux based with a lot of things per-configured

Pop!_OS is an operating system for STEM and creative professionals who use their computer as a tool to discover and create. Unleash your potential on secure, [...]

[Zero999]

The problem you're having is different programs use different graphical toolkits, which need to be configured separately. If I remember rightly, it's possible to set Gtk, so it just copies the theme set by Qt, or vice versa. All you need is a distribution, with the KDE desktop (assuming that's what you use, according to the OP) and the Gtk configured to follow Qt.

[JPortici]

Is there any OS with all the defaults to a dark mode?

macOS since a few versions

[ataradov]

Ubuntu Mate is dark by default. I don't like dark themes, but I use it in a VM for KiCad v6 experiments, and it seems to be pretty consistent. I see no obvious issue with it.

[neil555]

Windows 11?

[coromonadalix]

Windows 10  with unattended files / setups / and themes  can be installed in dark mode ....

yes its a tedious task  but it can be done

[SiliconWizard]

this is not a matter of preferences.

Of course it is. Not everyone wants exactly the same as you. 

Well, Gnome developers tend to think so.

[ataradov]

Gnome developers are something else, nothing like any other humans out there.

[Bassman59]

Gnome developers are something else, nothing like any other humans out there.

That's because they're gnomes, not humans.

Who didn't have this book as a kid?