How to disable screensaver/dpms/other power saving features

I have [a problem](https://unix.stackexchange.com/q/733329/47501) where monitors connected via docking station fail to reconnect if, I believe, the screensaver has been activated. I'm using debian testing without a desktop environment (ie only a window manager). gsettings says screensaver _should_ be disabled:

$ gsettings get org.gnome.desktop.session idle-delay
uint32 0
$ gsettings get org.gnome.desktop.screensaver lock-enabled
false

But overnight, while monitors are physically switched off (see the linked problem to see why), they fail to connect. **Question is** - what setting/command can switch power-saving/screensaver/anything related off so the screens are never turned off by software? I suspect dpms is the key here, but can't seem to disable it:

$ xset dpms 0 0 0
$ xset q
/--/
DPMS (Energy Star):
  Standby: 0    Suspend: 0    Off: 0
  DPMS is Enabled
  Monitor is On