Lock screen without blank in 18.04

When you lock your screen manually with Super + L just hold it a bit longer, then the screen will not blank immediately. It blanks after the time interval you set at Settings > Power > Blank Screen.

Edit: I tested it once again (this time it was chaging) and the screen did not blank when I locked my PC this way. It did not blank even after a few hours of idle time. So it probably only blanks when running on battery.

I was looking for a way around this, and I think I've finally got it!

Gnome Extension

I looked through the bug that was referenced here to find the link to that extension.

Check the current setting using:

gsettings get org.gnome.desktop.screensaver idle-activation-enabled

If the result is true turn it off using:

gsettings set org.gnome.desktop.screensaver idle-activation-enabled false

Second option to try is:

gsettings set org.gnome.settings-daemon.plugins.power idle-dim false

Gnome bug

There is a four year old Gnome bug addressing the issue of screen blanking immediately after lock here.