I just bought a two port KVM and it seems to function fine. However, my keyboard and mouse are not recognized by my M1 macbook pro. Everything is fine on my windows PC. I have a Caldigit TS4 that I use to dock my macbook to, and if I move the wireless adapters for my keyboard and mouse directly to the SAME port the KVM is connected to, they work fine. But through the KVM, they aren’t detected. Display switching works just fine though.
EDIT: If i connect the USB output of the KVM directly to my Macbook with a USB C to B cable, keyboard and mouse work fine. Seems to be an issue with the dock, but a 2 cable docking solution isn’t terrible (one cable for keyboard and mouse, and a second for display/network/audio interface etc)