Turning on/off the screen at the mentioned timings and other timings/combinations did not solve the problem.
Update: I've just visited my friend's house, he has the exact same monitor and motherboard model as mine, just an older bios (mine has the latest). I took my whole system with me. we tested the same port in the graphics card.
We unboxed his new MSI 1060 and tested it on my system, and it worked just fine.
Then we tested my 1080 on his system, and it worked just fine.
Then we placed my 1080 in my system again, and it worked just fine! (did not change anything in the bios/hardware/system).
if you were following this forum thread/topic, you would've seen that when I replaced my 1080 with my brother's 970 the issue was gone, restarting, shutting down, cold boot, nothing could reproduce the issue, until i did a windows update (security update to visual c++ redistributable) when the issue came back. the same thing happened now, when i place the 1060 in my system, then my 1080 back, the issue was gone once again, no beeps, no vg_led light that stays lit all the time, i can see and access the bios and safe mode.
At the moment the issue is gone, but it could come back after a windows update/random restart. I know that I need to place another graphics card in my system, post it, shut it down, then place the 1080 back to fix the issue, but I think this is a temporary solution, since the issue came back yesterday.
I think either the motherboard BIOS or the 1080's bios has a bug/issues.