Ati Yoga or Dzogchen is the topmost path as per the “Nine Yanas” or “nine successive vehicles” (within the Tibetan Nyingma tradition).

The full spectrum of the Buddhist spiritual paths is divided into nine yanas, a system of practice bringing together all the approaches
of the Buddha’s teaching into a single comprehensive path to enlightenment.

As per this model of comprehending the overall Buddhist teachings, there is:

  • Entry level Buddhist path (Hinayana, Sutrayana or small vehicle), a path of renunciation,
  • Mahayana, the great vehicle (also a path of renunciation and compassion as well),
  • Vajrayana, the Diamond vehicle (the path of transformation and compassion) and
  • Ati Yoga or Dzogchen, the path of instant awakening or instant presence.

More on this rather comprehensive model on Rigpa Shedra:
https://www.rigpawiki.org/index.php?title=Nine_yanas

Dzogchen or Ati Yoga provides teachings that surpass even the advanced Tantric practices, and it is by no means a short-cut.

The incomparable beauty of the Atiyoga or Dzogchen is that in itself it is beyond all mental fabrications, concepts, and dogmas:

To treat Dzogchen like an integrated philosophy or a subject of study
and analysis is to demonstrate ignorance that the Dzogchen view is a nondual view,
the unity of the subject/object dichotomy; that there can be no dogma,
doctrine or set practice in radical Dzogchen; that an analytical,
intellectual approach adds sand to the tank that was to provide the fuel for the journey;
that it hardens the arteries whose pliability and elasticity was our best hope for extra vitality.
– Dowman, Keith: Spaciousness, p. 24-25, Kindle Edition.

 

“Any attempt to search for or discover a state free from dogma
and limitation is like a blind bird searching for the end of space.
Nothing can be found. The meaning that nothing can be found
cannot be adjusted by anyone. It is impossible to find a
limitation with awareness that is free of elaboration.”
– Yeshe Lama, p. 57