Monitor (somewhat flaky) not detected under Gnome, only with Windows 10

I recently acquired a cheap HDMI monitor and I’ve been having a lot of trouble to get it to detect under Gnome in Linux. No matter if I plug it in at boot time or after the system loads, Gnome will not see it. I have tried on my laptop running both Fedora and Windows 10 as well as my main Arch system, but neither detect it.

Note that although the Arch system in question is a QEMU/KVM vm with a RX 480 passed through, I don’t think that has anything to do with it. Host system specs: Proxmox VE 6, Ryzen 7 2700X, Asus Prime X470 Pro.

Now, I would normally conclude that the monitor simply has a dead HDMI port from this, but I can get the monitor to come up when I boot a Windows 10 VM with the same RX480 passed through. It usually takes around 30 seconds for the screen to wake up after the system comes out of sleep, but other than that, it works fine. There must be something else going on since the Windows 10 laptop doesn’t detect it either.

Does anyone have experience with this? I am really at a loss. Is there maybe some kind of diagnostic I can run low-level in Linux?

Thanks for any help.

IDK maybe something like this?

Or maybe since it takes so long for the monitor to wake up even with Windows, maybe X server is giving up before then? IDK if you can set it for longer?

The laptop may not be outputting due to the settings for dual monitor. I know on my laptop I have to hit FN+F4 to switch between extended, mirrored, laptop only, and external display only settings. On your function keys look for a grayed icon which looks like a box in a box or montior bezel and screen.

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