Most tools in this space make you pick one: a KVM app for mouse/keyboard sharing, or a second-screen app for extending your display, never both. EasySwitch does both in one lightweight process. The bigger thing though is what it doesn't do - no cloud account, no upsell for encryption, LAN-only by default, and native Rust instead of another Electron app sitting at a few hundred MB of RAM idle just to move a cursor between two machines. For a desk with more than one computer that's exactly the right shape of tool.
Thanks for the solid feedback!
It actually creates a true virtual display driver that your OS registers as a real secondary monitor (showing up directly in your System Settings with native resolution and refresh rate controls, not just a windowed stream).
Plus, if you want to verify performance numbers yourself, turn on Settings -> Show stats on extended displays in EasySwitch to see live FPS, latency, dropped frames, and network speed. Give it a shot!