Remote desktop through hardware only

"It's 11 years after I needed a solution but as people still seem to answer it, I'm sharing how I've solved it...
First of all, as all PC's I need run Windows, I just got Mouse Without Borders which allows me to share a single keyboard and mouse between multiple computers.
Second of all, I now have multiple monitors as it's more practical to see everything I need.
This combined means I'm looking at 4 screens for 3 different computers and all I use is one mouse and one keyboard. It works great and has been working fine for several years now.
As for the dual-boot issue. That's no more requirement as the Windows Subsystem for Linux solved that issue for me."

You don't like KVM?? I think modern days KVM are quite stable, they (almost all) use solid-state switching instead of actual switching by mechanical switches.

If you decide to go with a KVM again, you can double-tap Scroll Lock and then hit the up or down cursor keys to cycle through connected machines. A lot easier than trying for the button on the KVM itself ...

"It's 11 years after I needed a solution but as people still seem to answer it, I'm sharing how I've solved it...
First of all, as all PC's I need run Windows, I just got Mouse Without Borders which allows me to share a single keyboard and mouse between multiple computers.
Second of all, I now have multiple monitors as it's more practical to see everything I need.
This combined means I'm looking at 4 screens for 3 different computers and all I use is one mouse and one keyboard. It works great and has been working fine for several years now.
As for the dual-boot issue. That's no more requirement as the Windows Subsystem for Linux solved that issue for me."