Looking for a KVM compatibility for Mac Studio, Studio Display, Windows PC

Let's start with; does your Windows computer have Thunderbolt 3/4 ports that carry display output from its GPU?

• If it does, then you would connect the PC → KVM host's TB4 port.
• If it doesn't this may still work, but will require a dedicated TB add-in card. One that come to mind is the TB4 (Maple Ridge). You would then feed it DP from your GPU, and then, connect that TB port to the KVM. (Note: The PC's Motherboard header and BIOS support will be required.)

Once the PC side is taken care of, we can move on to the KVM. A Sabrent SB-TB4K should work for this. It exposes three downstream TB4 ports (one would be used for the Studio Display) and switches between two TB4 hosts.

So, your setup would look something like the following:

• Mac side: Connect Mac Studio → KVM host TB4 port with a 0.8–1 m TB4/40Gbps cable.
• PC side: As I described above.
• Display: Plug the Studio Display into one of the KVM’s downstream TB4 ports.
• Peripherals: Plug keyboard/mouse and any shared USB gear into the KVM’s USB-A ports; they should follow the active host.

Apple Studio Display is a 5K display capable of 10 bits/color.

Connecting it at that data rate requires a data rate that very nearly saturates a Thunderbolt -3 or -4 cable. No slower connection will suffice.

Studio Display - Technical Specifications - Apple