DELL U3415W monitor goes blank/black randomly, using HDMI from iMac 2017

ISSUE: "DELL U3415W monitor goes blank/black randomly, using HDMI from iMac 2017"

I have this issue where the DELL U3415W monitor randomly goes blank, so all I see is a black screen for about 5 seconds, then it goes back to normal. I have not solved this problem. If someone has solved this issue, please post your solution.

Below are experiments that I have attempted that have failed to solve the issue.

DEBUG:

• EXPERIMENT 1:
  • DISABLE DDC/CI (Display Data Channel/Command Interface):
  • Maybe the iMac is feeding information to monitor causing it to attempt to switch inputs or go into power saving mode. So I disabled DDC/CI. From the U3415W Operating Manual: "DDC/CI (Display Data Channel/Command Interface) allows your monitor parameters (brightness, color balance, and etc.) to be adjustable via the software on your computer. You can disable this feature by selecting Disable. Enable this feature for best user experience and optimum performance of your monitor."
• RESULT:
  • FAILED.
  • Issue persists.

• EXPERIMENT 2:
  • SET PBP (Picture by Picture), PBP (Sub) => DP or MHL
  • Maybe even though the PBP is off, the monitor may still be searching for the input.
• RESULT:
  • FAILED.
  • Issue persists.

• EXPERIMENT 3:
  • SET Display, DP (Daisy Chain) 1.2 => Enable
  • Maybe the multi monitor mode needs to be enabled.
• RESULT:
  • FAILED.
  • Issue persists.

• EXPERIMENT 4:
  • DISCONNECT ANY INPUTS NEXT TO HDMI INTO CONVERTER TO IMAC.
  • I have three input converter to the latest USB. One of the inputs is HDM, but I had a fitbit charger on one of the inputs. When I wiggled the fitbit USB the monitor flickered, so I have disconnected it.
• RESULTS:

  FAILED, but issues occur much less often.