In the empty URP project template, inside Assets/Scripts/SimpleCameraController.cs, there's this like of code:

// Rotation
if (IsCameraRotationAllowed())
{
var mouseMovement = GetInputLookRotation() * Time.deltaTime * 5;

It incorrectly multiplies the mouse movement by delta time, causing it to become frame rate dependent. Mouse input is already frame independent as it's expressed in raw movement units, rather than a state (like keyboard keys) that affects movement over time.

Reproduction steps to see it in action:
1. Create an empty URP project
2. Enter playmode
3. Hold down the right mouse button to enable mouse look, move the mouse and notice its sensitivity.
4. Go to gameview settings and enable VSync
5. Hold down the right mouse button to enable mouse look, move the mouse and notice that the sensitivity isn't the same as it was before enabling VSync.