Hi NathanNSC,
Welcome to Microsoft Community.
It sounds like the USB-C cable you're using might not support the required specifications for proper video, data, and power transfer, which are necessary for the KVM functionality.
- USB-C Cable Compatibility: Cable Type: Not all USB-C cables support video output or data transfer for peripherals like keyboards and mice. Ensure your USB-C cable is rated for DisplayPort Alt Mode and supports USB data for KVM functionality. For optimal performance with Surface products, using USB4/Thunderbolt™ 4 certified cables is advised.
- Test Each Input Separately: Try connecting the Surface to the USB-C input without involving the KVM switch to see if it can output video properly. If it works, the KVM switch might not handle the input properly.
- Resolution and Refresh Rate Settings: Sometimes, the Surface might default to a resolution or refresh rate that the monitor can't handle. You can try connecting directly to the monitor first to set a compatible resolution. Once set, reconnect via USB-C and see if it helps.
If after trying these steps you're still experiencing issues, consider reaching out to the manufacturer of your KVM switch/monitors for more specialized assistance. It could be that there’s an inherent compatibility issue among the devices involved.
Your Sincerely
Hahn. W - MSFT | Microsoft Community Support Specialist