Quick answer: Godot 4 Input.warp_mouse causing visible cursor flicker on Windows? Native cursor and Godot's input state drift - hide the OS cursor or use captured mouse mode.
FPS controls use mouse warp to center the cursor. Cursor visibly jumps between positions on Windows.
Use captured mouse
Input.mouse_mode = Input.MOUSE_MODE_CAPTUREDOS hides the cursor; no warp needed. Mouse motion is delta-only, which is what FPS controls want anyway.
Or hide native cursor
Input.mouse_mode = MOUSE_MODE_HIDDEN plus your own drawn cursor. Cursor matches your input model exactly.
Throttle warps
If you must warp visible cursor, do it less often. Once per second feels less janky than once per frame.
“Mouse capture is the right primitive for relative-motion games.”
If your game expects locked mouse, opt into captured mode in the settings menu. Players who hate it can opt out; defaults match the gameplay intent.