My experience has been reasonably consistent. My main DE is KDE, it switches between light and dark based on my location and time. It switches to warmer colors at night. I have never had a problem in the applications I use.
I occasionally switch on the fancy effects like windows fall apart when I'm in the fun mode, or I'm showing something to friends, as a bit of fun makes everything more interesting, and all work perfectly well.
reply > If you set light mode, you'll get some light gray text on lighter gray background somewhere, but if you use dark mode, then you'll get some black text rendered on a black background elsewhere.