That’s right: any valid emission-flight-absorption “thread” we could imagine for a massless particle going at the speed of light from point A to point B is experienced by it as a single “knot” of existence. No space or time considerations involved at light speed.

That’s why causality is never violated, regardless of the observer point of view: The underlying reality of any process that matter observers can detect is always based in entanglement and instantaneity. All our spacetime processes are based on the instant happenings that take place for the massless quanta that compose reality each time.