I want to use the Comet Pro on my main PC that doubles as both my AI Stack and my Gaming PC. unfortunately, I do not believe the HDMI passthrough will work with nVidia G-Sync and high refresh rates. Is there a way to either use an HDMI splitter or feed the video to the Comet Pro without impacting the ability to use it as a gaming pc? I would never use both at the same time… so i would only need the Comet Pro when I am away, but having to yank the HDMI cable from one to the other would be a major pita… so I would like to avoid that. Anyone else done this or have an ideal on how to make it work?
Set up mirror screen , not using HDMI passthrough
It depends how the ports do connect on your pc it is a little difficult but there is a priority which ports gets first screen.
You could put for monitor on hdmi 1, and kvm on hdmi 2, or have monitor on displayport and kvm on hdmi 1, displayport has a higher priority than hdmi.
So when you go away, best is to turn off monitor, and for emergency you could use a smart plug so power is off (i know that is kinda cumbersome but works).
So here is what you can do:
Windows has memory for each monitor getting connected, which mean it will use the correct settings wether it should be mirrored or shutdown.
So if you game and main monitor is on, you can make the monitor only view on screen 1 in windows, the comet will be disconnected (turned off as screen), also the whole section from the bios loading it picks up only one signal at a time, it can only use one single monitor based on this port priority, only when windows boots more signals are possible, but if you configure to only show on screen 1 comet will be off.
If bios boots, the comet will only show screen if the monitor was manually powered off as hdmi fallback, but in Windows it will appear if the monitor was off and the comet is the only available monitor.
This is the setup I basiclly use, for remote gaming for the preperation to unlock my encrypted drive in bootloader I use kvm, but then I use software based streaming on sunshine/moonlight which spawn a virtual monitor which then shutsdown kvm, from the virtual monitor I have set it to only view on monitor 2.
This fork is called apollo for sunshine and artemis as client for moonlight.
I'm a little against mirroring or passthrough because sometimes it wants to mess with refresh rates or strips monitor functions like reflex, however virtual monitor don't support things like reflex or g-sync, but important to maintain the features of your main monitor when it is on 
, framegen relies extremely on reflex.
Not sure I understand - could you elaborate please!
As mentioned above, you need to first determine where you want your BIOS screen to display. If you want it to show on the local monitor, you must plug the local monitor into the first HDMI port of your graphics card. If you want the BIOS screen to appear in the KVM for convenient remote viewing, you need to connect the KVM to the first HDMI port of your graphics card.
Then, press Win + P to set your display configuration to mirror/Duplicated mode.