Simple question: how do you turn off the d*mn screen saver in Raspbian for Pi 3 Model B? It keeps popping up even if I leave Chromium looping a video in Kiosk mode. I tried the solution from this answer, but it does nothing to stop the screensaver from showing.
You should try using xscreensaver. You can easily disable screen saver using xscreensaver-demo, which will prompt a simple GUI config. In the Display Modes tab, you should see a drop-down list named Mode. From there select Disable Screen Saver and that should do the trick.
You don't have to use the graphical interface, here is a link to the manual if you are interested in looking at specific terminal commands etc: https://www.jwz.org/xscreensaver/man1.html