The monitor is connected to an HDMI port, tried the display port too with the same result. Searched for MB update too but nothing seems to be there. Yeah, my love for Linux won’t die anytime soon. Using it since the days of Mandrake Linux. But the “out of the box, more or less” experience I had on my laptops with arch and arch-based distros, is what turned me off on desktop.
Please, read carefully. What GPU? This looks like a desktop, so it is easy to recognize which port goes to each GPU, which is not as simple on laptops.
The rest of the comments are 
Maybe you could disable nvidia-resume.service: on the ArchWiki there’s written that systemd already handles the resume of NVIDIA cards internally, so that service may cause problems. I don’t think your problem is caused by that, but it’s worth to try. It’s so strange that the PC wakes up but the screen remains black, I was expecting it to crash completely