I'm the 0.01% of people who aren't happy that it's using QMK. Previously it had it's own mouse firmware, and I wish it was still actively maintained for this and the Ploopy Nano.
Due to the new QMK firmware, the Ploopy cannot be used simultaneously with some very expensive KVMs and KMs. That's because they are all built on the assumption that they are connected to one keyboard and one mouse.
I have tons of great QMK keyboards and I can't use them with the Ploopy on these switches because of this.
I understand your particular pain, but I want to share the flip side of it. QMK devices are great for me as a Mac user because it's very rare that any of the custom firmware configuration tools for input devices get ported to macOS. But QMK has a port and if a device wants to present itself as just a bog-standard USB device with all the "translation" happening on the device rather than requiring custom drivers and additional software on the OS side, everything just works. I presume users of other non-Windows OSes have similar takes, and I really hope the QMK trend gets picked up by Logitech, Kensington, and MS's hardware team eventually so that more hardware on the mass-market/affordable end of the spectrum can also do these things.
I don't have a QMK device to with, but from a quick look at the source code it looks like you could build QMK without MOUSE_ENABLE defined and flash that firmware to your keyboard to workaround the problem with your KVM. I would also consider opening an issue I would not be at all suprised if the devs have a better idea for how to deal with your quirky KVM
Interesting, I would've assumed they (the keyboard/mouse part) were just USB switches. What's the (supposed; not in your case) benefit to them doing any HID-aware stuff? No Windows 'device connected' bongs when you switch (because it's always identifying as the KVM, just not sending anything)? Anything else?
EDID emulation is great when you have multiple screens, and wish to prevent MS from randomly scattering your Windows all across your other screens every time you click to another input.
Due to the new QMK firmware, the Ploopy cannot be used simultaneously with some very expensive KVMs and KMs. That's because they are all built on the assumption that they are connected to one keyboard and one mouse.
I have tons of great QMK keyboards and I can't use them with the Ploopy on these switches because of this.