None of those are what the OP is asking for. The OP wants software that will allow the use of a keyboard and mouse between multiple computers with monitors attached.I use Microsoft Remote Desktop Connection to operate Windows systems from my Mac (or Windows system). I use RealVNC + Putty to operate my (remote) Mac tunneling through SSH from Windows. I use Screen Sharing to operate Macs from my Mac. I make use of XQuartz and ssh to operate Linux systems from my Mac and NoMachine to operate Linux systems from Windows.
I control Windows and Linux from a Mac on a daily basis and Macs and Linux from Windows more on a weekly basis, so it's all heavily used. Also, all the software is free.
I saw, which is why I commented no further. I use a single keyboard, monitor, and mouse to control many computers using software, but at one time I did use an unwieldy hardware KVM switch to do this.None of those are what the OP is asking for. The OP wants software that will allow the use of a keyboard and mouse between multiple computers with monitors attached.