Mac computer with KVM (no keyboard or mouse)

nothing more needs to be installed on a Mac.

Just use Finder, surf in the general direction of "Network" and once you specify a network device, will be offered a button in the header to (Share Screen) or (Connect As...) a specific user.

...

The Power required to run most Mac external keyboards is quite large compared to the power provided by a typical USB port. it is so large that although there are 'convenience' USB outlets on BOTH side of many Mac keyboards, the ONLY supported device is ONE low-power Mac mouse. ANYTHING more causes the keyboard to malfunction.

In addition, the keyboard is very sensitive to cable length. The approved genuine Mac keyboard extension cable is VERY short, and it keyed so that only ONE such extension can be used. it appears that longer cables also cause keyboard malfunctions.

I would like to suggest a different way to organize these Macs, provided you do not require full-motion Video on each Mac.

Instead of switching a physical display at frighteningly fast Video speeds, connect each Mac in turn using Mac Screen Sharing. This allows you to connect to each 'slave' Mac in turn. The slave Mac's display will appear in a window on the Master Mac. Typing on the Master Mac when that window is frontmost becomes direct keyboard input on the 'Slave' Mac.

One issue is, without some way to tell the remote slave Mac it has a display connected at startup, the default display created can be problematic and/or very small.

There is an inexpensive plug-in device that simply Fakes a connected HDMI display, and can give you up to a 4K fake display buffer to share through screen sharing.

https://eshop.macsales.com/item/NewerTech/ADP4KHEAD -- US$13

.

<< if that ethernet cable counts towards the length of the usb cable. >>

The fundamental problem is signal strength attenuation (weakening ) with excessive cable length. So addicting a repeater should fix the issue while allowing the distances you require.

But also consider the other solution is suggested above (it might not get emailed to you because I replied to myself) and look at Mac Screen Sharing as a 'no cost' solution that can perform just as well for everything except full-motion Video. This feature is also generally interoperable with VNC screen sharing, so you could get to linux or Windows machines in a similar way.

With 10 foot keyboard cables, YES, I do think it will mostly refuse to work.