You may try a GNOME shell extension as a workaround called Keep awake!
Product description:
Keep your computer awake! Forbid your computer to activate sceensaver, turn off the screen or suspend when it is idle for a while. Toogle [sic] this option on or off with one click.
Once you install this extension you'll see an "eye" icon in your top bar.

(screenshot source: extension's homepage at extensions.gnome.org)
Clicking on the eye will switch between "normal" and "no screen-lock or suspend" mode.
Another advanced extension which does the same but provides more customisability is Caffeine.
Warning: There is (or was, not sure whether it's fixed already) a bug in Caffeine which may freeze your computer for ~30 seconds after clicking on the power-off button in the status menu.
gnome-tweak
? In that program there are some settings that are not in the normal setttings. And yes it has a few I would consider needed (without it I could not set my system to NOT kill my wifi cuz gnome-tweak has an extra setting for "suspend" that was always ON despite normal settings it was set OFF). – Rinzwind Oct 26 '17 at 08:56gnome-tweak-tool
I believe. – pomsky Oct 26 '17 at 10:27disable screensaver
. It will prevent your screen from going dark. – Manish Kumar Bisht Nov 10 '17 at 16:24