External monitor blanks after 10 mins

I’ve experienced the following problem with two different Samsung external monitors on my Acer Helios. The screen will blank after 10 mins, completely ignoring my power saving settings (but the laptop screen stays on). After a longer period it seems to sleep/suspend and won’t wake up on keyboard or mouse events anymore. The only way I can restore it is by running xfce4-display-settings , switching on mirror display and then reverting back to the original setup (this sometimes fails too).

I haven’t found a combination of intel-virtual-output or xrandr that restores extended display profile either, although I use them in a script to set up my display profile initially after logging in.

Has anyone experienced this?

Did you check if there a standby mode or eco modus or something at the screen enabled?

Yes, I did check that. It’s switched off. I also should mention this does not happen under Windows.