I am new to Ubuntu but have been using mint for a few years. I am having problems with a second monitor.
I have Ubuntu 20.04.3 LTS 64 bit gnome 3.36.8 running on a AMD 32 core threadripper / 64GB / NVIDIA Corporation TU116 [GeForce GTX 1660 Ti] and 2 X 4K Lg monitors.
The issue comes when i turn the monitors off, only one turns back on. This happens whether the computer turns the monitors off or I do.
I am currently managing this by disabling any screen savers and changing the power setting so as they stay on all the time.
I have had a trawl through the forums and applied some of the suggestions like using dconf editor to change the settings.
The only inspiration I have is that the affected monitor is connected to the HDMI port.