Switching HDMI on 4K TV KDE no signal

After updating Manjaro to kernel 5.9 and Nvidia 455 my HTPC Vizio P-55 F1 3840X2160 @60HZ would go blank if I switched HDMI inputs and back. If I stayed on KDE and turn off the TV then when I turned it back on it would work fine but only when I switched Inputs did I lose signal.

So I started trouble shooting. I thought maybe it was a bad HDMI input and changed to another one. That didn’t work. Just so you know all four inputs are 3840X2160 @60HZ capable. Maybe the cable was the problem so I purchased a new HDMI 2.0 cable from amazon and no luck. Must be software related so I downgraded the kernel from 5.9 to 5.8, 5.7, and finally LTS 5.4 all while rebooting and testing nada. I was still using Nvidia 455 so I switched back to kernel 5.9 and installed Nvidia 450 and that did it.

I was on Manjaro testing repos and they just decided to stop all Nvidia driver downgrades through MHWD and only allow access to the most current one. This is one of the reasons I am using E-OS now but a strange thing happened.
I installed E-OS with KDE and the same thing happened. Not gonna give up. Since KDE doesn’t use a screensaver app since I’ve been on Manjaro I just assume when I setup the system I turn off all screen locking and energy saving settings and when I’m done using the system I just turn off the TV.
But I was happy to find when i reinstalled a second time and before I changed all those settings I was away from the system that it locked the screen. The screen was blank and when i touched the wireless keyboard it woke the system and I was able to login. So now I just set the Screen Energy Saving to whatever minutes and when the screen goes blank I can wake it up and all is well.

If you got any insight about my issues and solution I’m game. Hope this helped someone.

I think that is because it just blanks the screen but is not putting it into sleep mode. This is how it works on my kde setup. If it puts things into sleep it may have an issue re-energizing the port. Could be some settings in Bios for power management but personally i would leave it the way it is. I have another tv hooked to hdmi with xfce and i switch back and forth from tv and computer with no issue. Sometimes these issues can be the tv or cables or the software. Best to stick with what works.